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[转载]超线程Hyper-Threading和OpenMP
- 作者： zhouconghui 2006年08月5日, 星期六 01:20 回复（0） | 引用（0） 加入博采
[转]串口通讯基础及S3C2410 UART控制器
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- 作者： zhouconghui 2006年08月2日, 星期三 10:39 回复（0） | 引用（0） 加入博采
What Is Web 2.0
What Is Web 2.0
Design Patterns and Business Models for the Next Generation of Software
by Tim O'Reilly
09/30/2005
The bursting of the dot-com bubble in the fall of 2001 marked a turning point for the web. Many people concluded that the web was overhyped, when in fact bubbles and consequent shakeouts appear to be a common feature of all technological revolutions. Shakeouts typically mark the point at which an ascendant technology is ready to take its place at center stage. The pretenders are given the bum's rush, the real success stories show their strength, and there begins to be an understanding of what separates one from the other.
The concept of "Web 2.0" began with a conference brainstorming session between O'Reilly and MediaLive International. Dale Dougherty, web pioneer and O'Reilly VP, noted that far from having "crashed", the web was more important than ever, with exciting new applications and sites popping up with surprising regularity. What's more, the companies that had survived the collapse seemed to have some things in common. Could it be that the dot-com collapse marked some kind of turning point for the web, such that a call to action such as "Web 2.0" might make sense? We agreed that it did, and so the Web 2.0 Conference was born.
In the year and a half since, the term "Web 2.0" has clearly taken hold, with more than 9.5 million citations in Google. But there's still a huge amount of disagreement about just what Web 2.0 means, with some people decrying it as a meaningless marketing buzzword, and others accepting it as the new conventional wisdom.
This article is an attempt to clarify just what we mean by Web 2.0.
In our initial brainstorming, we formulated our sense of Web 2.0 by example:
| Web 1.0 | Web 2.0 | |
|---|---|---|
| DoubleClick | --> | Google AdSense |
| Ofoto | --> | Flickr |
| Akamai | --> | BitTorrent |
| mp3.com | --> | Napster |
| Britannica Online | --> | Wikipedia |
| personal websites | --> | blogging |
| evite | --> | upcoming.org and EVDB |
| domain name speculation | --> | search engine optimization |
| page views | --> | cost per click |
| screen scraping | --> | web services |
| publishing | --> | participation |
| content management systems | --> | wikis |
| directories (taxonomy) | --> | tagging ("folksonomy") |
| stickiness | --> | syndication |
The list went on and on. But what was it that made us identify one application or approach as "Web 1.0" and another as "Web 2.0"? (The question is particularly urgent because the Web 2.0 meme has become so widespread that companies are now pasting it on as a marketing buzzword, with no real understanding of just what it means. The question is particularly difficult because many of those buzzword-addicted startups are definitely not Web 2.0, while some of the applications we identified as Web 2.0, like Napster and BitTorrent, are not even properly web applications!) We began trying to tease out the principles that are demonstrated in one way or another by the success stories of web 1.0 and by the most interesting of the new applications.
1. The Web As Platform
Like many important concepts, Web 2.0 doesn't have a hard boundary, but rather, a gravitational core. You can visualize Web 2.0 as a set of principles and practices that tie together a veritable solar system of sites that demonstrate some or all of those principles, at a varying distance from that core.
Figure 1 shows a "meme map" of Web 2.0 that was developed at a brainstorming session during FOO Camp, a conference at O'Reilly Media. It's very much a work in progress, but shows the many ideas that radiate out from the Web 2.0 core.
For example, at the first Web 2.0 conference, in October 2004, John Battelle and I listed a preliminary set of principles in our opening talk. The first of those principles was "The web as platform." Yet that was also a rallying cry of Web 1.0 darling Netscape, which went down in flames after a heated battle with Microsoft. What's more, two of our initial Web 1.0 exemplars, DoubleClick and Akamai, were both pioneers in treating the web as a platform. People don't often think of it as "web services", but in fact, ad serving was the first widely deployed web service, and the first widely deployed "mashup" (to use another term that has gained currency of late). Every banner ad is served as a seamless cooperation between two websites, delivering an integrated page to a reader on yet another computer. Akamai also treats the network as the platform, and at a deeper level of the stack, building a transparent caching and content delivery network that eases bandwidth congestion.
Nonetheless, these pioneers provided useful contrasts because later entrants have taken their solution to the same problem even further, understanding something deeper about the nature of the new platform. Both DoubleClick and Akamai were Web 2.0 pioneers, yet we can also see how it's possible to realize more of the possibilities by embracing additional Web 2.0 design patterns.
Let's drill down for a moment into each of these three cases, teasing out some of the essential elements of difference.
Netscape vs. Google
If Netscape was the standard bearer for Web 1.0, Google is most certainly the standard bearer for Web 2.0, if only because their respective IPOs were defining events for each era. So let's start with a comparison of these two companies and their positioning.
Netscape framed "the web as platform" in terms of the old software paradigm: their flagship product was the web browser, a desktop application, and their strategy was to use their dominance in the browser market to establish a market for high-priced server products. Control over standards for displaying content and applications in the browser would, in theory, give Netscape the kind of market power enjoyed by Microsoft in the PC market. Much like the "horseless carriage" framed the automobile as an extension of the familiar, Netscape promoted a "webtop" to replace the desktop, and planned to populate that webtop with information updates and applets pushed to the webtop by information providers who would purchase Netscape servers.
In the end, both web browsers and web servers turned out to be commodities, and value moved "up the stack" to services delivered over the web platform.
Google, by contrast, began its life as a native web application, never sold or packaged, but delivered as a service, with customers paying, directly or indirectly, for the use of that service. None of the trappings of the old software industry are present. No scheduled software releases, just continuous improvement. No licensing or sale, just usage. No porting to different platforms so that customers can run the software on their own equipment, just a massively scalable collection of commodity PCs running open source operating systems plus homegrown applications and utilities that no one outside the company ever gets to see.
At bottom, Google requires a competency that Netscape never needed: database management. Google isn't just a collection of software tools, it's a specialized database. Without the data, the tools are useless; without the software, the data is unmanageable. Software licensing and control over APIs--the lever of power in the previous era--is irrelevant because the software never need be distributed but only performed, and also because without the ability to collect and manage the data, the software is of little use. In fact, the value of the software is proportional to the scale and dynamism of the data it helps to manage.
Google's service is not a server--though it is delivered by a massive collection of internet servers--nor a browser--though it is experienced by the user within the browser. Nor does its flagship search service even host the content that it enables users to find. Much like a phone call, which happens not just on the phones at either end of the call, but on the network in between, Google happens in the space between browser and search engine and destination content server, as an enabler or middleman between the user and his or her online experience.
While both Netscape and Google could be described as software companies, it's clear that Netscape belonged to the same software world as Lotus, Microsoft, Oracle, SAP, and other companies that got their start in the 1980's software revolution, while Google's fellows are other internet applications like eBay, Amazon, Napster, and yes, DoubleClick and Akamai.
DoubleClick vs. Overture and AdSense
Like Google, DoubleClick is a true child of the internet era. It harnesses software as a service, has a core competency in data management, and, as noted above, was a pioneer in web services long before web services even had a name. However, DoubleClick was ultimately limited by its business model. It bought into the '90s notion that the web was about publishing, not participation; that advertisers, not consumers, ought to call the shots; that size mattered, and that the internet was increasingly being dominated by the top websites as measured by MediaMetrix and other web ad scoring companies.
As a result, DoubleClick proudly cites on its website "over 2000 successful implementations" of its software. Yahoo! Search Marketing (formerly Overture) and Google AdSense, by contrast, already serve hundreds of thousands of advertisers apiece.
Overture and Google's success came from an understanding of what Chris Anderson refers to as "the long tail," the collective power of the small sites that make up the bulk of the web's content. DoubleClick's offerings require a formal sales contract, limiting their market to the few thousand largest websites. Overture and Google figured out how to enable ad placement on virtually any web page. What's more, they eschewed publisher/ad-agency friendly advertising formats such as banner ads and popups in favor of minimally intrusive, context-sensitive, consumer-friendly text advertising.
The Web 2.0 lesson: leverage customer-self service and algorithmic data management to reach out to the entire web, to the edges and not just the center, to the long tail and not just the head.
A Platform Beats an Application Every TimeIn each of its past confrontations with rivals, Microsoft has successfully played the platform card, trumping even the most dominant applications. Windows allowed Microsoft to displace Lotus 1-2-3 with Excel, WordPerfect with Word, and Netscape Navigator with Internet Explorer. This time, though, the clash isn't between a platform and an application, but between two platforms, each with a radically different business model: On the one side, a single software provider, whose massive installed base and tightly integrated operating system and APIs give control over the programming paradigm; on the other, a system without an owner, tied together by a set of protocols, open standards and agreements for cooperation. Windows represents the pinnacle of proprietary control via software APIs. Netscape tried to wrest control from Microsoft using the same techniques that Microsoft itself had used against other rivals, and failed. But Apache, which held to the open standards of the web, has prospered. The battle is no longer unequal, a platform versus a single application, but platform versus platform, with the question being which platform, and more profoundly, which architecture, and which business model, is better suited to the opportunity ahead. Windows was a brilliant solution to the problems of the early PC era. It leveled the playing field for application developers, solving a host of problems that had previously bedeviled the industry. But a single monolithic approach, controlled by a single vendor, is no longer a solution, it's a problem. Communications-oriented systems, as the internet-as-platform most certainly is, require interoperability. Unless a vendor can control both ends of every interaction, the possibilities of user lock-in via software APIs are limited. Any Web 2.0 vendor that seeks to lock in its application gains by controlling the platform will, by definition, no longer be playing to the strengths of the platform. This is not to say that there are not opportunities for lock-in and competitive advantage, but we believe they are not to be found via control over software APIs and protocols. There is a new game afoot. The companies that succeed in the Web 2.0 era will be those that understand the rules of that game, rather than trying to go back to the rules of the PC software era. |
Not surprisingly, other web 2.0 success stories demonstrate this same behavior. eBay enables occasional transactions of only a few dollars between single individuals, acting as an automated intermediary. Napster (though shut down for legal reasons) built its network not by building a centralized song database, but by architecting a system in such a way that every downloader also became a server, and thus grew the network.
Akamai vs. BitTorrent
Like DoubleClick, Akamai is optimized to do business with the head, not the tail, with the center, not the edges. While it serves the benefit of the individuals at the edge of the web by smoothing their access to the high-demand sites at the center, it collects its revenue from those central sites.
BitTorrent, like other pioneers in the P2P movement, takes a radical approach to internet decentralization. Every client is also a server; files are broken up into fragments that can be served from multiple locations, transparently harnessing the network of downloaders to provide both bandwidth and data to other users. The more popular the file, in fact, the faster it can be served, as there are more users providing bandwidth and fragments of the complete file.
BitTorrent thus demonstrates a key Web 2.0 principle: the service automatically gets better the more people use it. While Akamai must add servers to improve service, every BitTorrent consumer brings his own resources to the party. There's an implicit "architecture of participation", a built-in ethic of cooperation, in which the service acts primarily as an intelligent broker, connecting the edges to each other and harnessing the power of the users themselves.
2. Harnessing Collective Intelligence
The central principle behind the success of the giants born in the Web 1.0 era who have survived to lead the Web 2.0 era appears to be this, that they have embraced the power of the web to harness collective intelligence:
- Hyperlinking is the foundation of the web. As users add new content, and new sites, it is bound in to the structure of the web by other users discovering the content and linking to it. Much as synapses form in the brain, with associations becoming stronger through repetition or intensity, the web of connections grows organically as an output of the collective activity of all web users.
- Yahoo!, the first great internet success story, was born as a catalog, or directory of links, an aggregation of the best work of thousands, then millions of web users. While Yahoo! has since moved into the business of creating many types of content, its role as a portal to the collective work of the net's users remains the core of its value.
- Google's breakthrough in search, which quickly made it the undisputed search market leader, was PageRank, a method of using the link structure of the web rather than just the characteristics of documents to provide better search results.
- eBay's product is the collective activity of all its users; like the web itself, eBay grows organically in response to user activity, and the company's role is as an enabler of a context in which that user activity can happen. What's more, eBay's competitive advantage comes almost entirely from the critical mass of buyers and sellers, which makes any new entrant offering similar services significantly less attractive.
- Amazon sells the same products as competitors such as Barnesandnoble.com, and they receive the same product descriptions, cover images, and editorial content from their vendors. But Amazon has made a science of user engagement. They have an order of magnitude more user reviews, invitations to participate in varied ways on virtually every page--and even more importantly, they use user activity to produce better search results. While a Barnesandnoble.com search is likely to lead with the company's own products, or sponsored results, Amazon always leads with "most popular", a real-time computation based not only on sales but other factors that Amazon insiders call the "flow" around products. With an order of magnitude more user participation, it's no surprise that Amazon's sales also outpace competitors.
Now, innovative companies that pick up on this insight and perhaps extend it even further, are making their mark on the web:
- Wikipedia, an online encyclopedia based on the unlikely notion that an entry can be added by any web user, and edited by any other, is a radical experiment in trust, applying Eric Raymond's dictum (originally coined in the context of open source software) that "with enough eyeballs, all bugs are shallow," to content creation. Wikipedia is already in the top 100 websites, and many think it will be in the top ten before long. This is a profound change in the dynamics of content creation!
- Sites like del.icio.us and Flickr, two companies that have received a great deal of attention of late, have pioneered a concept that some people call "folksonomy" (in contrast to taxonomy), a style of collaborative categorization of sites using freely chosen keywords, often referred to as tags. Tagging allows for the kind of multiple, overlapping associations that the brain itself uses, rather than rigid categories. In the canonical example, a Flickr photo of a puppy might be tagged both "puppy" and "cute"--allowing for retrieval along natural axes generated user activity.
- Collaborative spam filtering products like Cloudmark aggregate the individual decisions of email users about what is and is not spam, outperforming systems that rely on analysis of the messages themselves.
- It is a truism that the greatest internet success stories don't advertise their products. Their adoption is driven by "viral marketing"--that is, recommendations propagating directly from one user to another. You can almost make the case that if a site or product relies on advertising to get the word out, it isn't Web 2.0.
- Even much of the infrastructure of the web--including the Linux, Apache, MySQL, and Perl, PHP, or Python code involved in most web servers--relies on the peer-production methods of open source, in themselves an instance of collective, net-enabled intelligence. There are more than 100,000 open source software projects listed on SourceForge.net. Anyone can add a project, anyone can download and use the code, and new projects migrate from the edges to the center as a result of users putting them to work, an organic software adoption process relying almost entirely on viral marketing.
The lesson: Network effects from user contributions are the key to market dominance in the Web 2.0 era.
Blogging and the Wisdom of Crowds
One of the most highly touted features of the Web 2.0 era is the rise of blogging. Personal home pages have been around since the early days of the web, and the personal diary and daily opinion column around much longer than that, so just what is the fuss all about?
At its most basic, a blog is just a personal home page in diary format. But as Rich Skrenta notes, the chronological organization of a blog "seems like a trivial difference, but it drives an entirely different delivery, advertising and value chain."
One of the things that has made a difference is a technology called RSS. RSS is the most significant advance in the fundamental architecture of the web since early hackers realized that CGI could be used to create database-backed websites. RSS allows someone to link not just to a page, but to subscribe to it, with notification every time that page changes. Skrenta calls this "the incremental web." Others call it the "live web".
Now, of course, "dynamic websites" (i.e., database-backed sites with dynamically generated content) replaced static web pages well over ten years ago. What's dynamic about the live web are not just the pages, but the links. A link to a weblog is expected to point to a perennially changing page, with "permalinks" for any individual entry, and notification for each change. An RSS feed is thus a much stronger link than, say a bookmark or a link to a single page.
The Architecture of ParticipationSome systems are designed to encourage participation. In his paper, The Cornucopia of the Commons, Dan Bricklin noted that there are three ways to build a large database. The first, demonstrated by Yahoo!, is to pay people to do it. The second, inspired by lessons from the open source community, is to get volunteers to perform the same task. The Open Directory Project, an open source Yahoo competitor, is the result. But Napster demonstrated a third way. Because Napster set its defaults to automatically serve any music that was downloaded, every user automatically helped to build the value of the shared database. This same approach has been followed by all other P2P file sharing services. One of the key lessons of the Web 2.0 era is this: Users add value. But only a small percentage of users will go to the trouble of adding value to your application via explicit means. Therefore, Web 2.0 companies set inclusive defaults for aggregating user data and building value as a side-effect of ordinary use of the application. As noted above, they build systems that get better the more people use them. Mitch Kapor once noted that "architecture is politics." Participation is intrinsic to Napster, part of its fundamental architecture. This architectural insight may also be more central to the success of open source software than the more frequently cited appeal to volunteerism. The architecture of the internet, and the World Wide Web, as well as of open source software projects like Linux, Apache, and Perl, is such that users pursuing their own "selfish" interests build collective value as an automatic byproduct. Each of these projects has a small core, well-defined extension mechanisms, and an approach that lets any well-behaved component be added by anyone, growing the outer layers of what Larry Wall, the creator of Perl, refers to as "the onion." In other words, these technologies demonstrate network effects, simply through the way that they have been designed. These projects can be seen to have a natural architecture of participation. But as Amazon demonstrates, by consistent effort (as well as economic incentives such as the Associates program), it is possible to overlay such an architecture on a system that would not normally seem to possess it. |
RSS also means that the web browser is not the only means of viewing a web page. While some RSS aggregators, such as Bloglines, are web-based, others are desktop clients, and still others allow users of portable devices to subscribe to constantly updated content.
RSS is now being used to push not just notices of new blog entries, but also all kinds of data updates, including stock quotes, weather data, and photo availability. This use is actually a return to one of its roots: RSS was born in 1997 out of the confluence of Dave Winer's "Really Simple Syndication" technology, used to push out blog updates, and Netscape's "Rich Site Summary", which allowed users to create custom Netscape home pages with regularly updated data flows. Netscape lost interest, and the technology was carried forward by blogging pioneer Userland, Winer's company. In the current crop of applications, we see, though, the heritage of both parents.
But RSS is only part of what makes a weblog different from an ordinary web page. Tom Coates remarks on the significance of the permalink:
It may seem like a trivial piece of functionality now, but it was effectively the device that turned weblogs from an ease-of-publishing phenomenon into a conversational mess of overlapping communities. For the first time it became relatively easy to gesture directly at a highly specific post on someone else's site and talk about it. Discussion emerged. Chat emerged. And - as a result - friendships emerged or became more entrenched. The permalink was the first - and most successful - attempt to build bridges between weblogs.
In many ways, the combination of RSS and permalinks adds many of the features of NNTP, the Network News Protocol of the Usenet, onto HTTP, the web protocol. The "blogosphere" can be thought of as a new, peer-to-peer equivalent to Usenet and bulletin-boards, the conversational watering holes of the early internet. Not only can people subscribe to each others' sites, and easily link to individual comments on a page, but also, via a mechanism known as trackbacks, they can see when anyone else links to their pages, and can respond, either with reciprocal links, or by adding comments.
Interestingly, two-way links were the goal of early hypertext systems like Xanadu. Hypertext purists have celebrated trackbacks as a step towards two way links. But note that trackbacks are not properly two-way--rather, they are really (potentially) symmetrical one-way links that create the effect of two way links. The difference may seem subtle, but in practice it is enormous. Social networking systems like Friendster, Orkut, and LinkedIn, which require acknowledgment by the recipient in order to establish a connection, lack the same scalability as the web. As noted by Caterina Fake, co-founder of the Flickr photo sharing service, attention is only coincidentally reciprocal. (Flickr thus allows users to set watch lists--any user can subscribe to any other user's photostream via RSS. The object of attention is notified, but does not have to approve the connection.)
If an essential part of Web 2.0 is harnessing collective intelligence, turning the web into a kind of global brain, the blogosphere is the equivalent of constant mental chatter in the forebrain, the voice we hear in all of our heads. It may not reflect the deep structure of the brain, which is often unconscious, but is instead the equivalent of conscious thought. And as a reflection of conscious thought and attention, the blogosphere has begun to have a powerful effect.
First, because search engines use link structure to help predict useful pages, bloggers, as the most prolific and timely linkers, have a disproportionate role in shaping search engine results. Second, because the blogging community is so highly self-referential, bloggers paying attention to other bloggers magnifies their visibility and power. The "echo chamber" that critics decry is also an amplifier.
If it were merely an amplifier, blogging would be uninteresting. But like Wikipedia, blogging harnesses collective intelligence as a kind of filter. What James Suriowecki calls "the wisdom of crowds" comes into play, and much as PageRank produces better results than analysis of any individual document, the collective attention of the blogosphere selects for value.
While mainstream media may see individual blogs as competitors, what is really unnerving is that the competition is with the blogosphere as a whole. This is not just a competition between sites, but a competition between business models. The world of Web 2.0 is also the world of what Dan Gillmor calls "we, the media," a world in which "the former audience", not a few people in a back room, decides what's important.
3. Data is the Next Intel Inside
Every significant internet application to date has been backed by a specialized database: Google's web crawl, Yahoo!'s directory (and web crawl), Amazon's database of products, eBay's database of products and sellers, MapQuest's map databases, Napster's distributed song database. As Hal Varian remarked in a personal conversation last year, "SQL is the new HTML." Database management is a core competency of Web 2.0 companies, so much so that we have sometimes referred to these applications as "infoware" rather than merely software.
This fact leads to a key question: Who owns the data?
In the internet era, one can already see a number of cases where control over the database has led to market control and outsized financial returns. The monopoly on domain name registry initially granted by government fiat to Network Solutions (later purchased by Verisign) was one of the first great moneymakers of the internet. While we've argued that business advantage via controlling software APIs is much more difficult in the age of the internet, control of key data sources is not, especially if those data sources are expensive to create or amenable to increasing returns via network effects.
Look at the copyright notices at the base of every map served by MapQuest, maps.yahoo.com, maps.msn.com, or maps.google.com, and you'll see the line "Maps copyright NavTeq, TeleAtlas," or with the new satellite imagery services, "Images copyright Digital Globe." These companies made substantial investments in their databases (NavTeq alone reportedly invested $750 million to build their database of street addresses and directions. Digital Globe spent $500 million to launch their own satellite to improve on government-supplied imagery.) NavTeq has gone so far as to imitate Intel's familiar Intel Inside logo: Cars with navigation systems bear the imprint, "NavTeq Onboard." Data is indeed the Intel Inside of these applications, a sole source component in systems whose software infrastructure is largely open source or otherwise commodified.
The now hotly contested web mapping arena demonstrates how a failure to understand the importance of owning an application's core data will eventually undercut its competitive position. MapQuest pioneered the web mapping category in 1995, yet when Yahoo!, and then Microsoft, and most recently Google, decided to enter the market, they were easily able to offer a competing application simply by licensing the same data.
Contrast, however, the position of Amazon.com. Like competitors such as Barnesandnoble.com, its original database came from ISBN registry provider R.R. Bowker. But unlike MapQuest, Amazon relentlessly enhanced the data, adding publisher-supplied data such as cover images, table of contents, index, and sample material. Even more importantly, they harnessed their users to annotate the data, such that after ten years, Amazon, not Bowker, is the primary source for bibliographic data on books, a reference source for scholars and librarians as well as consumers. Amazon also introduced their own proprietary identifier, the ASIN, which corresponds to the ISBN where one is present, and creates an equivalent namespace for products without one. Effectively, Amazon "embraced and extended" their data suppliers.
Imagine if MapQuest had done the same thing, harnessing their users to annotate maps and directions, adding layers of value. It would have been much more difficult for competitors to enter the market just by licensing the base data.
The recent introduction of Google Maps provides a living laboratory for the competition between application vendors and their data suppliers. Google's lightweight programming model has led to the creation of numerous value-added services in the form of mashups that link Google Maps with other internet-accessible data sources. Paul Rademacher's housingmaps.com, which combines Google Maps with Craigslist apartment rental and home purchase data to create an interactive housing search tool, is the pre-eminent example of such a mashup.
At present, these mashups are mostly innovative experiments, done by hackers. But entrepreneurial activity follows close behind. And already, one can see that for at least one class of developer, Google has taken the role of data source away from Navteq and inserted themselves as a favored intermediary. We expect to see battles between data suppliers and application vendors in the next few years, as both realize just how important certain classes of data will become as building blocks for Web 2.0 applications.
The race is on to own certain classes of core data: location, identity, calendaring of public events, product identifiers and namespaces. In many cases, where there is significant cost to create the data, there may be an opportunity for an Intel Inside style play, with a single source for the data. In others, the winner will be the company that first reaches critical mass via user aggregation, and turns that aggregated data into a system service.
For example, in the area of identity, PayPal, Amazon's 1-click, and the millions of users of communications systems, may all be legitimate contenders to build a network-wide identity database. (In this regard, Google's recent attempt to use cell phone numbers as an identifier for Gmail accounts may be a step towards embracing and extending the phone system.) Meanwhile, startups like Sxip are exploring the potential of federated identity, in quest of a kind of "distributed 1-click" that will provide a seamless Web 2.0 identity subsystem. In the area of calendaring, EVDB is an attempt to build the world's largest shared calendar via a wiki-style architecture of participation. While the jury's still out on the success of any particular startup or approach, it's clear that standards and solutions in these areas, effectively turning certain classes of data into reliable subsystems of the "internet operating system", will enable the next generation of applications.
A further point must be noted with regard to data, and that is user concerns about privacy and their rights to their own data. In many of the early web applications, copyright is only loosely enforced. For example, Amazon lays claim to any reviews submitted to the site, but in the absence of enforcement, people may repost the same review elsewhere. However, as companies begin to realize that control over data may be their chief source of competitive advantage, we may see heightened attempts at control.
Much as the rise of proprietary software led to the Free Software movement, we expect the rise of proprietary databases to result in a Free Data movement within the next decade. One can see early signs of this countervailing trend in open data projects such as Wikipedia, the Creative Commons, and in software projects like Greasemonkey, which allow users to take control of how data is displayed on their computer.
4. End of the Software Release Cycle
As noted above in the discussion of Google vs. Netscape, one of the defining characteristics of internet era software is that it is delivered as a service, not as a product. This fact leads to a number of fundamental changes in the business model of such a company:
- Operations must become a core competency. Google's or Yahoo!'s expertise in product development must be matched by an expertise in daily operations. So fundamental is the shift from software as artifact to software as service that the software will cease to perform unless it is maintained on a daily basis. Google must continuously crawl the web and update its indices, continuously filter out link spam and other attempts to influence its results, continuously and dynamically respond to hundreds of millions of asynchronous user queries, simultaneously matching them with context-appropriate advertisements.
It's no accident that Google's system administration, networking, and load balancing techniques are perhaps even more closely guarded secrets than their search algorithms. Google's success at automating these processes is a key part of their cost advantage over competitors.
It's also no accident that scripting languages such as Perl, Python, PHP, and now Ruby, play such a large role at web 2.0 companies. Perl was famously described by Hassan Schroeder, Sun's first webmaster, as "the duct tape of the internet." Dynamic languages (often called scripting languages and looked down on by the software engineers of the era of software artifacts) are the tool of choice for system and network administrators, as well as application developers building dynamic systems that require constant change.
- Users must be treated as co-developers, in a reflection of open source development practices (even if the software in question is unlikely to be released under an open source license.) The open source dictum, "release early and release often" in fact has morphed into an even more radical position, "the perpetual beta," in which the product is developed in the open, with new features slipstreamed in on a monthly, weekly, or even daily basis. It's no accident that services such as Gmail, Google Maps, Flickr, del.icio.us, and the like may be expected to bear a "Beta" logo for years at a time.
Real time monitoring of user behavior to see just which new features are used, and how they are used, thus becomes another required core competency. A web developer at a major online service remarked: "We put up two or three new features on some part of the site every day, and if users don't adopt them, we take them down. If they like them, we roll them out to the entire site."
Cal Henderson, the lead developer of Flickr, recently revealed that they deploy new builds up to every half hour. This is clearly a radically different development model! While not all web applications are developed in as extreme a style as Flickr, almost all web applications have a development cycle that is radically unlike anything from the PC or client-server era. It is for this reason that a recent ZDnet editorial concluded that Microsoft won't be able to beat Google: "Microsoft's business model depends on everyone upgrading their computing environment every two to three years. Google's depends on everyone exploring what's new in their computing environment every day."
While Microsoft has demonstrated enormous ability to learn from and ultimately best its competition, there's no question that this time, the competition will require Microsoft (and by extension, every other existing software company) to become a deeply different kind of company. Native Web 2.0 companies enjoy a natural advantage, as they don't have old patterns (and corresponding business models and revenue sources) to shed.
A Web 2.0 Investment ThesisVenture capitalist Paul Kedrosky writes: "The key is to find the actionable investments where you disagree with the consensus". It's interesting to see how each Web 2.0 facet involves disagreeing with the consensus: everyone was emphasizing keeping data private, Flickr/Napster/et al. make it public. It's not just disagreeing to be disagreeable (pet food! online!), it's disagreeing where you can build something out of the differences. Flickr builds communities, Napster built breadth of collection. Another way to look at it is that the successful companies all give up something expensive but considered critical to get something valuable for free that was once expensive. For example, Wikipedia gives up central editorial control in return for speed and breadth. Napster gave up on the idea of "the catalog" (all the songs the vendor was selling) and got breadth. Amazon gave up on the idea of having a physical storefront but got to serve the entire world. Google gave up on the big customers (initially) and got the 80% whose needs weren't being met. There's something very aikido (using your opponent's force against them) in saying "you know, you're right--absolutely anyone in the whole world CAN update this article. And guess what, that's bad news for you." --Nat Torkington |
5. Lightweight Programming Models
Once the idea of web services became au courant, large companies jumped into the fray with a complex web services stack designed to create highly reliable programming environments for distributed applications.
But much as the web succeeded precisely because it overthrew much of hypertext theory, substituting a simple pragmatism for ideal design, RSS has become perhaps the single most widely deployed web service because of its simplicity, while the complex corporate web services stacks have yet to achieve wide deployment.
Similarly, Amazon.com's web services are provided in two forms: one adhering to the formalisms of the SOAP (Simple Object Access Protocol) web services stack, the other simply providing XML data over HTTP, in a lightweight approach sometimes referred to as REST (Representational State Transfer). While high value B2B connections (like those between Amazon and retail partners like ToysRUs) use the SOAP stack, Amazon reports that 95% of the usage is of the lightweight REST service.
This same quest for simplicity can be seen in other "organic" web services. Google's recent release of Google Maps is a case in point. Google Maps' simple AJAX (Javascript and XML) interface was quickly decrypted by hackers, who then proceeded to remix the data into new services.
Mapping-related web services had been available for some time from GIS vendors such as ESRI as well as from MapQuest and Microsoft MapPoint. But Google Maps set the world on fire because of its simplicity. While experimenting with any of the formal vendor-supported web services required a formal contract between the parties, the way Google Maps was implemented left the data for the taking, and hackers soon found ways to creatively re-use that data.
There are several significant lessons here:
- Support lightweight programming models that allow for loosely coupled systems. The complexity of the corporate-sponsored web services stack is designed to enable tight coupling. While this is necessary in many cases, many of the most interesting applications can indeed remain loosely coupled, and even fragile. The Web 2.0 mindset is very different from the traditional IT mindset!
- Think syndication, not coordination. Simple web services, like RSS and REST-based web services, are about syndicating data outwards, not controlling what happens when it gets to the other end of the connection. This idea is fundamental to the internet itself, a reflection of what is known as the end-to-end principle.
- Design for "hackability" and remixability. Systems like the original web, RSS, and AJAX all have this in common: the barriers to re-use are extremely low. Much of the useful software is actually open source, but even when it isn't, there is little in the way of intellectual property protection. The web browser's "View Source" option made it possible for any user to copy any other user's web page; RSS was designed to empower the user to view the content he or she wants, when it's wanted, not at the behest of the information provider; the most successful web services are those that have been easiest to take in new directions unimagined by their creators. The phrase "some rights reserved," which was popularized by the Creative Commons to contrast with the more typical "all rights reserved," is a useful guidepost.
Innovation in Assembly
Lightweight business models are a natural concomitant of lightweight programming and lightweight connections. The Web 2.0 mindset is good at re-use. A new service like housingmaps.com was built simply by snapping together two existing services. Housingmaps.com doesn't have a business model (yet)--but for many small-scale services, Google AdSense (or perhaps Amazon associates fees, or both) provides the snap-in equivalent of a revenue model.
These examples provide an insight into another key web 2.0 principle, which we call "innovation in assembly." When commodity components are abundant, you can create value simply by assembling them in novel or effective ways. Much as the PC revolution provided many opportunities for innovation in assembly of commodity hardware, with companies like Dell making a science out of such assembly, thereby defeating companies whose business model required innovation in product development, we believe that Web 2.0 will provide opportunities for companies to beat the competition by getting better at harnessing and integrating services provided by others.
6. Software Above the Level of a Single Device
One other feature of Web 2.0 that deserves mention is the fact that it's no longer limited to the PC platform. In his parting advice to Microsoft, long time Microsoft developer Dave Stutz pointed out that "Useful software written above the level of the single device will command high margins for a long time to come."
Of course, any web application can be seen as software above the level of a single device. After all, even the simplest web application involves at least two computers: the one hosting the web server and the one hosting the browser. And as we've discussed, the development of the web as platform extends this idea to synthetic applications composed of services provided by multiple computers.
But as with many areas of Web 2.0, where the "2.0-ness" is not something new, but rather a fuller realization of the true potential of the web platform, this phrase gives us a key insight into how to design applications and services for the new platform.
To date, iTunes is the best exemplar of this principle. This application seamlessly reaches from the handheld device to a massive web back-end, with the PC acting as a local cache and control station. There have been many previous attempts to bring web content to portable devices, but the iPod/iTunes combination is one of the first such applications designed from the ground up to span multiple devices. TiVo is another good example.
iTunes and TiVo also demonstrate many of the other core principles of Web 2.0. They are not web applications per se, but they leverage the power of the web platform, making it a seamless, almost invisible part of their infrastructure. Data management is most clearly the heart of their offering. They are services, not packaged applications (although in the case of iTunes, it can be used as a packaged application, managing only the user's local data.) What's more, both TiVo and iTunes show some budding use of collective intelligence, although in each case, their experiments are at war with the IP lobby's. There's only a limited architecture of participation in iTunes, though the recent addition of podcasting changes that equation substantially.
This is one of the areas of Web 2.0 where we expect to see some of the greatest change, as more and more devices are connected to the new platform. What applications become possible when our phones and our cars are not consuming data but reporting it? Real time traffic monitoring, flash mobs, and citizen journalism are only a few of the early warning signs of the capabilities of the new platform.
7. Rich User Experiences
As early as Pei Wei's Viola browser in 1992, the web was being used to deliver "applets" and other kinds of active content within the web browser. Java's introduction in 1995 was framed around the delivery of such applets. JavaScript and then DHTML were introduced as lightweight ways to provide client side programmability and richer user experiences. Several years ago, Macromedia coined the term "Rich Internet Applications" (which has also been picked up by open source Flash competitor Laszlo Systems) to highlight the capabilities of Flash to deliver not just multimedia content but also GUI-style application experiences.
However, the potential of the web to deliver full scale applications didn't hit the mainstream till Google introduced Gmail, quickly followed by Google Maps, web based applications with rich user interfaces and PC-equivalent interactivity. The collection of technologies used by Google was christened AJAX, in a seminal essay by Jesse James Garrett of web design firm Adaptive Path. He wrote:
"Ajax isn't a technology. It's really several technologies, each flourishing in its own right, coming together in powerful new ways. Ajax incorporates:
- standards-based presentation using XHTML and CSS;
- dynamic display and interaction using the Document Object Model;
- data interchange and manipulation using XML and XSLT;
- asynchronous data retrieval using XMLHttpRequest;
- and JavaScript binding everything together."
Web 2.0 Design PatternsIn his book, A Pattern Language, Christopher Alexander prescribes a format for the concise description of the solution to architectural problems. He writes: "Each pattern describes a problem that occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice."
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AJAX is also a key component of Web 2.0 applications such as Flickr, now part of Yahoo!, 37signals' applications basecamp and backpack, as well as other Google applications such as Gmail and Orkut. We're entering an unprecedented period of user interface innovation, as web developers are finally able to build web applications as rich as local PC-based applications.
Interestingly, many of the capabilities now being explored have been around for many years. In the late '90s, both Microsoft and Netscape had a vision of the kind of capabilities that are now finally being realized, but their battle over the standards to be used made cross-browser applications difficult. It was only when Microsoft definitively won the browser wars, and there was a single de-facto browser standard to write to, that this kind of application became possible. And while Firefox has reintroduced competition to the browser market, at least so far we haven't seen the destructive competition over web standards that held back progress in the '90s.
We expect to see many new web applications over the next few years, both truly novel applications, and rich web reimplementations of PC applications. Every platform change to date has also created opportunities for a leadership change in the dominant applications of the previous platform.
Gmail has already provided some interesting innovations in email, combining the strengths of the web (accessible from anywhere, deep database competencies, searchability) with user interfaces that approach PC interfaces in usability. Meanwhile, other mail clients on the PC platform are nibbling away at the problem from the other end, adding IM and presence capabilities. How far are we from an integrated communications client combining the best of email, IM, and the cell phone, using VoIP to add voice capabilities to the rich capabilities of web applications? The race is on.
It's easy to see how Web 2.0 will also remake the address book. A Web 2.0-style address book would treat the local address book on the PC or phone merely as a cache of the contacts you've explicitly asked the system to remember. Meanwhile, a web-based synchronization agent, Gmail-style, would remember every message sent or received, every email address and every phone number used, and build social networking heuristics to decide which ones to offer up as alternatives when an answer wasn't found in the local cache. Lacking an answer there, the system would query the broader social network.
A Web 2.0 word processor would support wiki-style collaborative editing, not just standalone documents. But it would also support the rich formatting we've come to expect in PC-based word processors. Writely is a good example of such an application, although it hasn't yet gained wide traction.
Nor will the Web 2.0 revolution be limited to PC applications. Salesforce.com demonstrates how the web can be used to deliver software as a service, in enterprise scale applications such as CRM.
The competitive opportunity for new entrants is to fully embrace the potential of Web 2.0. Companies that succeed will create applications that learn from their users, using an architecture of participation to build a commanding advantage not just in the software interface, but in the richness of the shared data.
Core Competencies of Web 2.0 Companies
In exploring the seven principles above, we've highlighted some of the principal features of Web 2.0. Each of the examples we've explored demonstrates one or more of those key principles, but may miss others. Let's close, therefore, by summarizing what we believe to be the core competencies of Web 2.0 companies:
- Services, not packaged software, with cost-effective scalability
- Control over unique, hard-to-recreate data sources that get richer as more people use them
- Trusting users as co-developers
- Harnessing collective intelligence
- Leveraging the long tail through customer self-service
- Software above the level of a single device
- Lightweight user interfaces, development models, AND business models
The next time a company claims that it's "Web 2.0," test their features against the list above. The more points they score, the more they are worthy of the name. Remember, though, that excellence in one area may be more telling than some small steps in all seven.
Tim O'Reilly
O’Reilly Media, Inc., tim@oreilly.com
President and CEO
- 作者： zhouconghui 2006年07月30日, 星期日 18:52 回复（0） | 引用（0） 加入博采
什么是Web 2.0
什么是Web 2.0 |
| 2005-11-22 10:50 来源:互联网周刊 作者:Tim O'Reilly |
2001年秋天互联网公司（dot-com)泡沫的破灭标志着互联网的一个转折点。许多人断定互联网被过分炒作，事实上网络泡沫和相继而来的股市大衰退看起来像是所有技术革命的共同特征。股市大衰退通常标志着蒸蒸日上的技术已经开始占领中央舞台。假冒者被驱逐，而真正成功的故事展示了它们的力量，同时人们开始理解了是什么将一个故事同另外一个区分开来。
“Web 2.0”的概念开始于一个会议中，展开于O'Reilly公司和MediaLive国际公司之间的头脑风暴部分。所谓互联网先驱和O'Reilly公司副总裁的戴尔·多尔蒂(Dale Dougherty)注意到，同所谓的“崩溃”迥然不同，互联网比其他任何时候都更重要，令人激动的新应用程序和网站正在以令人惊讶的规律性涌现出来。更重要的是，那些幸免于当初网络泡沫的公司，看起来有一些共同之处。那么会不会是互联网公司那场泡沫的破灭标志了互联网的一种转折，以至于呼吁“Web 2.0”的行动有了意义？我们都认同这种观点，Web 2.0会议由此诞生。
在那个会议之后的一年半的时间里，“Web 2.0”一词已经深入人心，从Google上可以搜索到950万以上的链接。但是，至今关于Web 2.0的含义仍存在极大的分歧，一些人将Web 2.0贬低为毫无疑义的一个行销炒作口号，而其他一些人则将之理解为一种新的传统理念。
本文就是来尝试澄清Web 2.0本来意义。
在我们当初的头脑风暴中，我们已经用一些例子，公式化地表达了我们对Web 2.0的理解：
| Web 1.0 | Web 2.0 |
| DoubleClick | Google AdSense |
| Ofoto | Flickr |
| Akamai | BitTorrent |
| mp3.com | Napster |
| 大英百科全书在线（Britannica Online） | 维基百科全书（Wikipedia） |
| 个人网站 | 博客(blogging) |
| evite | upcoming.org和EVDB |
| 域名投机 | 搜索引擎优化 |
| 页面浏览数 | 每次点击成本 |
| 屏幕抓取（screen scraping） | 网络服务（web services） |
| 发布 | 参与 |
| 内容管理系统 | 维基 |
| 目录（分类) | 标签（“分众分类”，folksonomy） |
| 粘性 | 聚合 |
这个列表还会不断继续下去。但是到底是什么，使得我们认定一个应用程序或一种方式为作所谓“Web 1.0”，而把另外一个叫做“Web 2.0”呢？（这个问题尤为紧迫，因为Web 2.0的观念已经传播的如此广泛，以至于很多公司正在将这个词加到他们的行销炒作中，但却没有真正理解其含义。同时这个问题也尤为困难，因为许多嗜好口号的创业公司显然不是Web 2.0，而一些我们认为是Web 2.0的应用程序，例如Napster和BitTorrent，甚至不是真正适当的网络程序！）我们首先来探讨一些原则，这些原则是通过Web 1.0的一些成功案例，以及一些最为有趣的新型应用程序来体现的。
1. 互联网作为平台
正如许多重要的理念一样，Web 2.0没有一个明确的界限，而是一个重力核心。不妨将Web 2.0视作一组原则和实践，由此来把距离核心或远或近的网站组成为一个类似太阳系的网络系统，这些网站或多或少地体现着Web 2.0的原则。
图1为Web 2.0的“模拟图”，该图是在名为“O'Reilly的朋友”（Friend Of O’reilly, FOO）的会议的一个研讨会上产生的。这个图基本上仍处于演化阶段，但已经描绘出了 从Web 2.0核心理念中衍生出的许多概念。
例如，在2004年10月的第一次Web 2.0的会议上，约翰·巴特利（John Battelle）和我在我们各自的开场白中列举了一组初步的原则。
这些原则中的第一条就是“互联网作为平台”。这也曾是Web 1.0的宠儿网景公司（Netscape)的战斗口号，而网景在同微软的大战中陨落了。此外，我们早先的Web 1.0的楷模中的两个，DoubleClick和Akamai公司，皆是将网络当作平台的先驱。人们往往不认为这是一种网络服务，但事实上，广告服务是第一个被广泛应用的网络服务，同时也是第一个被广泛应用的混合处理（mashup），如果用另一个近来流行的词来说的话。每个旗帜广告（banner ad)都是用来在两个网站之前无缝合作，向位于另外一台计算机上的读者传递一个整合好的页面。
Akamai也将网络看作平台，并且在一个更深入的层次上，来搭建一个透明的缓存和内容分发网络，以便降低宽带的拥塞程度。
虽然如此，这些先驱提供了有益的对比，因为后来者遇到同样问题的时候，可以将先驱们的解决方案进一步延伸，从而对新平台本质的理解也更为深刻了。DoubleClick和Akamai都是Web 2.0的先驱，同时我们也可以看到，可以通过引入更多Web 2.0的设计模式，来实现更多的应用。
让我们对这三个案例中的每一个都作一番深究，来探讨其间的一些本质性的差别。
Netscape 对 Google
如果Netscape可以称为Web 1.0的旗手，那么Google几乎可以肯定是Web 2.0的旗手，只要看看他们的首次公开上市（IPO)是如何地揭示了各自的时代就清楚了。所以我们就从这两个公司和其定位的差别入手。
Netscape以传统的软件摹本来勾勒其所谓“互联网作为平台”：他们的旗舰产品是互联网浏览器，一个桌面应用程序。同时，他们的战略是利用他们在浏览器市场的统治地位，来为其昂贵的服务器产品建立起市场。从理论上讲，在浏览器中控制显示内容和程序的标准，赋予了Netscape一种市场支配力，如同微软公司在个人计算机市场上所享受的一样。很像当初“自行的马车”（horseless carriage）将汽车描绘为一种熟知事物的延伸，Netscape曾推销一种网络桌面（webtop）来替代传统的桌面（desktop），并且计划借助信息更新，以及由购买了Netscape服务器的信息提供者来推送的各种小程序，来开发推广这种网络桌面。
最终，浏览器和网络服务器都变成了“日用品”，同时价值链条也向上移动到了在互联网平台上传递的服务。
作为对比，Google则以天生的网络应用程序的角色问世，它从不出售或者打包其程序，而是以服务的方式来传递。客户们直接或间接地为其所使用的服务向Google付费。原有软件工业缺陷荡然无存。没有了定期的软件发布，只需要持续的改善。没有了许可证或销售，只需要使用。没有了为了让用户在其设备上运行软件而不得不进行的平台迁移，只需要搭建宏大的、由众多个人计算机组成的、可伸缩的网络，其上运行开源操作系统，及其及自行研制的应用程序和工具，而公司之外的任何人则永远无法接触到这些东西。
在其底层，Google需要一种Netscape从未需要过的能力：数据库管理。Google远远不只是一个软件工具的集合，它是一个专业化的数据库。没有这些数据，那些工具将毫无用武之地；没有这些软件，数据也将无可控制。软件许可证制度和对应用程序接口（API）的控制——上一个时代的法宝——已经毫不相关了，因为Google的软件只需要执行而从不需要分发，也因为如果不具备收集和管理数据的能力，软件本身就没有什么用处了。事实上，软件的价值是同它所协助管理的数据的规模和活性成正比的。
Google的服务不是一个简单的服务器，虽然其服务是通过大规模的互联网服务器集合来传递的；其服务也不是一个浏览器，虽然这种服务是被用户在浏览器中体验到的。Google的旗舰产品——搜索服务，甚至不托管它让用户来搜寻的内容。很像一个电话通话过程，不仅发生在通话的两端，而且发生在中间的网络上。作为用户和其在线体验的一个中介，Google作用于浏览器、搜索引擎和最终的内容服务器之间的空间中。
虽然Netscape和Google都可以被描述为软件公司，但显然Netscape可以归到Lotus，Microsoft，Oracle，SAP，以及其他发源于上个世纪八十年代软件革命的那些公司所组成的软件世界。而Google的同伴们，则是像eBay，Amazon，Napster，及至DoubleClick和Akamai这样的互联网公司。
DoubleClick对Overture和AdSense
同Google类似，DoubleClick是一个名副其实的互联网时代的孩子。它把软件作为一种服务，在数据管理方面具有核心竞争力，并且正如上文所述，它是一个早在连网络服务的名字还不曾有的时候，就已然开始其服务的先驱。然而，DoubleClick最终还是被其商业模式局限住了。它所贯彻的是九十年代的互联网观念。这种观念围绕着出版，而不是参与；围绕着广告客户，而不是消费者，来进行操纵；围绕着规模，认为互联网会被如MediaMetrix等网络广告评测公司尺度下的所谓顶级网站所统治。
结果是，DoubleClick得意地在其网站上引用道：“超过2000种的成功应用”。而相对比的是，Yahoo!公司的搜索市场（从前的Overture）和Google的AdSense产品，已经在为几十万的广告客户服务。
Overture和Google的成功源自于对克里斯·安德森（Chris Anderson）提到的所谓“长尾”的领悟，即众多小网站集体的力量提供了互联网的大多数内容。DoubleClick的产品要求一种签订正式的销售合同，并将其市场局限于很少的几千个大型网站。Overture和Google则领会到如何将广告放置到几乎所有网页上。更进一步地，它们回避了发行商和广告代理们所喜爱的广告形式，例如旗帜广告和弹出式广告，而采用了干扰最小的、上下文敏感的、对用户友好的文字广告形式。
Web 2.0的经验是：有效利用消费者的自助服务和算法上的数据管理，以便能够将触角延伸至整个互联网，延伸至各个边缘而不仅仅是中心，延伸至长尾而不仅仅是头部。
毫不奇怪，其他Web 2.0的成功故事也显示着同样的轨迹。eBay扮演着一个自动的中间媒介的角色，使个体之间发生的几个美元的偶然性的交易成为可能。Napster（虽然已经出于法律原因而关闭）将其网络建立在一个集中的歌曲数据库之上，但是它让每一个下载者都成为一台服务器，从而使其网络逐渐扩大。
Akamai 对 BitTorrent
同DoubleClick类似，Akamai的业务重点面向网络的头部，而不是尾部；面向中心，而不是边缘。虽然它服务于那些处于网络边缘的个体的利益，为他们访问位于互联网中心的高需求的网站铺平了道路，但它的收入仍然来自从那些位于中心的网站。
BitTorrent，像P2P风潮中的其他倡导者一样，采用了一种激进的方式来达到互联网去中心化（internet decentralization）的目的。每个客户端同时也是一个服务器；文件被分割成许多片段，从而可以由网络上的多个地方提供，透明地利用了网络的下载者来为其他下载者提供带宽和数据。事实上，文件越流行下载得越快，因为有更多的用户在为这个文件提供带宽和各个片段。
BitTorrent由此显示出Web 2.0的一个关键原则：用户越多，服务越好。一边是Akamai必须增加服务器来改善服务，另一边是BitTorrent用户将各自的资源贡献给大家。可以说，有一种隐性的“参与体系”内置在合作准则中。在这种参与体系中，服务主要扮演着一个智能代理的作用，将网络上的各个边缘连接起来，同时充分利用了用户自身的力量。
2. 利用集体智慧
在诞生于Web 1.0时代并且存活了下来，而且要继续领导Web 2.0时代的那些巨人的成功故事的背后，有一个核心原则，就是他们借助了网络的力量来利用集体智慧：
--超级链接是互联网的基础。当用户添加新的内容和新的网站的时候，将被限定在一种特定的网络结构中，这种网络结构是由其他用户发现内容并建立链接的。如同大脑中的神经突触，随着彼此的联系通过复制和强化变得越来越强，而作为所有网络用户的所有活动的直接结果，互联的网络将有机地成长。
--Yahoo!是第首例伟大的成功故事，诞生于一个分类目录，或者说是链接目录，一个对数万甚至数百万网络用户的最精彩作品的汇总。虽然后来Yahoo!进入了创建五花八门的内容的业务，但其作为一个门户来收集网络用户们集体作品的角色，依然是其价值核心。
--Google在搜索方面的突破在于PageRank技术，该技术令其迅速成为搜索市场上毫无争议的领导者。PageRank是一种利用了网络的链接结构，而不是仅仅是使用文档的属性，来实现更好的搜索效果的方法。
--eBay的产品是其全部用户的集体活动，就向网络自身一样，eBay随着用户的活动而有机地成长，而且该公司的角色是作为一个特定环境的促成者，而用户的行动就发生在这种环境之中。更重要的是，eBay的竞争优势几乎都来自于关键性的大量的买家和卖家双方，而这正是这一点使得后面许多竞争者的产品的吸引力显著减低。
--Amazon销售同Barnesandnoble.com等竞争者相同的产品，同时这些公司从卖方获得的是同样的产品描述、封面图片和目录。所不同的是，Amazon已然缔造出了一门关于激发用户参与的科学。Amazon拥有比其竞争者高出一个数量级以上的用户评价，以及更多的邀请来让用户以五花八门的方式，在近乎所有的页面上进行参与，而更为重要的是，他们利用用户的活动来产生更好的搜索结果。Barnesandnoble.com的搜索结果很可能指向该公司自己的产品，或者是赞助商的结果，而Amazon则始终以所谓“最流行的”打头，这是一种实时计算，不仅基于销售，而且基于其他一些被Amazon内部人士称为围绕着产品“流动”（flow）的因素。由于拥有高出对手一个数量级的用户参与，Amazon销售额超出竞争对手也就不足为奇了。
现在，具备了这种洞察力，并且可能会将之延伸开来的那些创新型的公司，正在互联网上留下他们的印迹。
维基百科全书（Wikipedia）是一种在线百科全书，其实现基于一种看似不可能的观念。该观念认为一个条目可以被任何互联网用户所添加，同时可以被其他任何人编辑。无疑，这是对信任的一种极端的实验，将埃里克·雷蒙德（Eric Raymond）的格言（源自开放源码软件的背景之下）：“有足够的眼球，所有的程序缺陷都是肤浅的”（with enough eyeballs, all bugs are shallow）运用到了内容的创建之中。维基百科全书已然高居世界网站百强之列，并且许多人认为它不久就将位列十强。这在内容创建方面是一种深远的变革。
像del.icio.us（美味书签）和Flickr这样的网站，其公司已经在近期获得了广泛的关注，并且已经在一种被人们成为“分众分类”（folksonomy，有别于传统分类法）的概念上成为先行者。“分众分类”是一种使用用户自由选择的关键词对网站进行协作分类的方式，而这些关键词一般称为标签（tags)。标签化运用了像大脑本身所使用的那种多重的、重叠的关联，而不是死板的分类。举一个经典的例子，在Flickr网站上，一幅小狗照片可能被加上“小狗”和“可爱”这样的标签，从而允许系统依照用户行为所产生的自然的方式来进行检索。
协作式垃圾信息过滤产品，例如Cloudmark，就聚集了电子邮件用户们对于“一封邮件是或者不是垃圾邮件”的众多相互独立的决策，从而胜过了依赖于分析邮件本身的那些系统。
伟大的互联网成功者并不主动地到处推销其产品，这几乎成为公理。他们采用“病毒式营销”（viral marketing）的方式，也就是说，一些推介会直接从一个用户传播到另外一个用户。如何一个网站或产品依赖广告来进行宣传，你几乎可以断定它不是Web 2.0。
即便许多互联网基础设施本身，包括在大多数网络服务器中用到的Linux，Apache，MySQL，以及Perl，PHP或Python代码，也都依靠开放源码的对等生产（peer-production）的方式。其中包含了一种集体的、网络赋予的智慧。在SourceForge.net网站上列有至少10万种开放源码软件项目。任何人都可以添加一个项目，任何人都可以下载并使用项目代码。
同时，由于作为用户使用的结果，新的项目从边缘迁移到中心。一个对软件的有机的接受过程几乎完全依靠病毒式营销。同时，作为用户应用的结果，新的项目从边缘迁移到中心，这是一种几乎完全依靠病毒式营销的，有机的软件采用过程，。
经验是：源于用户贡献的网络效应，是在Web 2.0时代中统治市场的关键。
| 平台总是打败应用程序 在过去每次同对手的竞争中，微软都成功地打用了平台这张牌，打败了即便是最占主导地位的应用程序。Windows平台让微软以Excel取代了Lotus 1-2-3，以Word取代了WordPerfect,，以Internet Explorer取代了Netscape浏览器。 不过这次，冲突不是在平台和应用程序之间，而是在两种平台之间。每个平台皆有一种截然不同的商业模式：一方面，一个独立软件商具有广泛的用户基础并且将应用程序接口和操作系统紧密集成，从而对程序设计模式予以控制；另一方面，是一个没有所有者的系统，由一组协议、开放标准和对合作的共识来连结到一起。 Windows系统代表了由软件程序接口来进行专有控制的高峰。Netscape曾尝试用微软当初对付其对手所使用的手段，来同微软进行争夺，但是失败了。然而拥有互联网开放标准的Apache却已经繁荣了起来。此番上演的战局，已经不再是实力悬殊的平台对决孤立的软件了，而是变成了平台对决平台。问题在于，哪个平台，或者更深远地来说哪个体系，以及哪个商业模式，最能适应未来的机遇。 Windows对于早期的PC时代的问题是一种卓越的解决方案。它统一了程序开发者的竞技场，解决了很多困扰这个领域的问题。但这种由单一供方控制的一刀切的方法，已经不再是适宜的解决方案，而成为了一种问题。面向交流的系统需要协同性，互联网作为一个平台当然也是如此。除非供方可以控制每一例交互的两个终端，这种通过软件的程序接口来锁定用户的可能性微乎其微。 任何企图通过控制平台来推销应用程序的Web 2.0提供商，从定义上讲，已经丧失了这个平台的优越性。 这并不是说锁定和竞争优势的机会不复存在了，而是说我们相信这种机会不是通过控制软件程序接口和协议来取得的。新的游戏规则正在浮现。那些能够理解这些新的游戏规则，而不是企图回到PC软件时代旧有规则的公司，才有可能在Web 2.0时代获得成功。 |
博客和大众智慧
Web 2.0时代一项最受追捧的特性就是博客的兴起。个人主页从互联网早期就已经存在了，而个人日记和每日发表观点的专栏就更渊源久远了，那么到底有什么让人大惊小怪的呢？
归根底地，博客只是一种日记形式个人网页。但正如里奇·斯格仁塔（Rich Skrenta）指出的，博客的按时间顺序来排列的结构“看起来像是一个微不足道的变化，但却推动着一个迥然不同的分发、广告和价值链。”
其中一大变化就是一项称为RSS的技术。RSS是自早期计算机高手们认识到CGI（公共网关接口）可用来创建以数据库为基础的网站以来，在互联网根本结构方面最重要的进步。RSS使人们不仅仅链接到一个网页，而且可以订阅这个网页，从而每当该页面产生了变化时都会得到通知。斯格仁塔将之称为“增量的互联网”（incremental web）。其他人则称之为“鲜活的互联网”（live web）。
当然，现在所谓“动态网站”（即具有动态产生的内容的、由数据库驱动的网站）取代了十年前的静态网站。而动态网站的活力不仅在于网页，而且在链接方面。一个指向网络博客的链接实际上是指向一个不断更新的网页，包括指向其中任何一篇文章的“固定链接”（permalinks），以及每一次更新的通知。因此，一个RSS是比书签或者指向一个单独网页的链接要强大得多。
RSS同时也意味着网页浏览器不再只是限于浏览网页的工具。尽管诸如Bloglines之类的RSS聚合器（RSS aggregators）是基于网络的，但其他的则是桌面程序，此外还有一些则可以用在便携设备上来接受定期更新的内容。
RSS现在不仅用于推送新的博客文章的通知，还可以用于其他各种各样的数据更新，包括股票报价、天气情况、以及图片。这类应用实际上是对RSS本源的一种回归：RSS诞生于1997年，是如下两种技术的汇合：一种是戴夫·温纳（Dave Winer）的“真正简单的聚合”（Really Simple Syndication）技术，用于通知博客的更新情况；另一种是Netscape公司提供的“丰富站点摘要”（Rich Site Summary）技术，该技术允许用户用定期更新的数据流来定制Netscape主页。后来Netscape公司失去了兴趣，这种技术便由温纳的一个博客先驱公司Userland承接下来。不过，在现在的应用程序实现中，我可以看出两者共同的作用。
但是，RSS只是令博客区别于同普通网页的一部分原因。汤姆·科特斯（Tom Coates）这样评论固定链接的重要性：
“现在它可能看上去像是一项普普通通的功能，但它却有效地将博客从一个易于发布（ease-of-publishing）的现象，进一步转变为互相交叉的社区的一种对话式的参与。这是首次使得对其他人的网站上的很特定的帖子表态和谈论变得如此地容易。讨论出现了，聊天也出现。同时，其结果是出现了友谊或者友谊更加坚定了。固定链接是第一次也是最为成功的一次在博客之间搭建桥梁的尝试。”
在许多方面，RSS同固定链接的结合，为HTPP（互联网协议）增添了NNTP（新闻组的网络新闻协议）的许多特性。所谓“博客圈”（blogosphere），可以将其视作一种同互联网早期的、以对话方式来灌水的新闻组和公告牌相比来说，新型的对等（peer-to-peer）意义上的等价现象。人们不仅可以相互订阅网站并方便地链接到一个页面上的特定评论，而且通过一种称为引用通告（trackbacks）的机制，可以得知其他任何人链接到了他们的页面，并且可以用相互链接或者添加评论的方式来做出回应。
有趣的是，这种双向链接（two-way links）曾是象Xanadu之类的早期超文本系统的目标。超文本纯粹论者已然将引用通告颂扬为向双向链接迈进了一步。但需要注意的是，引用通告不是一个真正的双向链接，确切地讲是一种（潜在地）实现了双向链接效果的对称式单向链接。其间的区别看起来可能很细微，但实际上却是巨大的。诸如Friendster, Orkut和LinkedIn那样的社交网络系统（social networking systems），需要接受方做出确认以便建立某种连接，从而缺少像互联网架构本身那样的可伸缩性。正如照片共享服务Flickr网站的创始人之一卡特里纳·费克（Caterina Fake）所指出的，注意力仅在碰巧时才礼尚往来。（Flickr因此允许用户设置观察列表，即任何用户都可以通过RSS来订阅其他所有用户的照片流。注意的对象将会被通知，但并不一定要认可这种连接。）
如果Web 2.0的一个本质是利用集体智慧，来将互联网调试为一种所谓的全球的大脑，那么博客圈就是前脑中喋喋不休的呓语，那种我们整个头脑中都能听到的声音。这可能并不反映出大脑的往往是无意识的深层结构，但却是一种有意识的思考的等价物。作为一种有意识的思考和注意力的反映，博客圈已经开始具有强有力的影响。
首先，因为搜索引擎使用链接结构来辅助预测有用的页面，作为最多产和最及时的链接者，博客们在修整搜索引擎结果方面充当着一种不成比例的角色。其次，因为博客社区是如此多地自相引用，关注其他博客的博客们开阔了他们的视野和能力。此外，评论家们所批判的“回音室”（echo chamber）也是一种放大器。
如果只是一种放大器，那么撰写博客将会变得无趣。但是像维基百科全书一样，博客将集体智慧用作一种过滤器。被詹姆士·苏瑞奥维奇（James Suriowecki）称为“大众智慧”（the wisdom of crowds）的规律起了作用，并且就像PageRank技术所产生的结果胜过分析任何单一文档一样，博客圈的集体关注会筛选出有价值的东西。
虽然主流媒体可能将个别的博客视为竞争者，但真正使其紧张的将是同作为一个整体的博客圈的竞争。这不仅是网站之间的竞争，而且是一种商业模式之间的竞争。Web 2.0的世界也正是丹·吉尔默（Dan Gillmor）的所谓“个人媒体”（We，the media)的世界。在这个世界中，是所谓“原本的听众”，而不是密实里的少数几个人，来决定着什么是重要的。
3. 数据是下一个Intel Inside
现在每一个重要的互联网应用程序都由一个专门的数据库驱动：Google的网络爬虫, Yahoo!的目录（和网络爬虫），Amazon的产品数据库，eBay的产品数据库和销售商，MapQuest的地图数据库，Napster的分布式歌曲库。正如哈尔·瓦里安（Hal Varian）在去年的私人对话中谈到的，“SQL是新的HTML”。数据库管理是Web 2.0公司的核心竞争力，其重要性使得我们有时候称这些程序为“讯件”（infoware）而不仅仅是软件。
该事实也引出了一个关键问题：谁拥有数据？
在互联网时代，我们可能已经见到了这样一些案例，其中对数据库的掌控导致了对市场的支配和巨大的经济回报。当初由美国政府的法令授权给Network Solutions公司（后被Verisign公司收购）的对域名注册的垄断，曾经是互联网上的第一个摇钱树。虽然我们在争论通过控制软件的API来形成商业优势在互联网时代会变得困难得多，但是对关键数据资源的控制则不同，特别是当要创建这些数据资源非常昂贵，或者经由网络效应容易增加回报的时候。
注意一下由MapQuest, maps.yahoo.com，maps.msn.com，或者maps.google.com等网站提供的每张地图下面的版权声明，你会发现这样一行字“地图版权NavTeq，TeleAtlas”，或者如果使用的是新的卫星图像服务，则会看到“图像版权Digital Globe”的字样。这些公司对其数据库进行了大量的投资。（仅NavTeq一家，就公布投资7.5亿美元用于创建其街道地址和路线数据库。Digital Globe则投资5亿美元来启动其自有卫星，来对政府提供的图像进行改进。）NavTeq竟然已做了很多模仿Intel的耳熟能详的Intel Inside标识的事：例如带有导航系统的汽车就带有“NavTeq Onboard”的印记。数据是许多此类程序事实上的Intel Inside，是一些系统的唯一的信息源组件，这些系统的软件体系多数是开放源码的，也有商业化的。
当前竞争火热的网络地图（web mapping）领域显示着，对拥有软件核心数据的重要性的疏忽大意，将最终削弱其竞争地位。MapQuest在1995年率先进入地图领域，随后是Yahoo!，再后来是Microsoft，而最近Google也决定挺进这一市场，他们可以轻松地通过对同一数据的授权来提供一个具有竞争力的程序。
然而，作为对比的是Amazon.com的竞争地位。像Barnesandnoble.com这样的竞争者一样，其原始数据库来自于ISBN注册商.R. Bowker。但是同MapQuest不同，Amazon大力增强其数据，增加出版商提供的数据，例如封面图片，目录，索引，和样张材料。更重要的是，他们利用了其用户来评注数据，以至于十年之后，是Amazon而不是Bowker，成为图书文献信息的主要来源，一个学者、图书管理员和消费者的参考书目来源。Amazon还引入了其专有的标识符，即ASIN，该标识符在ISBN存在时与之对应，而当产品不带有ISBN时，就创建出一个等价的命名空间。Amazon从而有效地“吸收和拓展了”其数据提供商。
设想如果MapQuest也已做了同样的事情，利用他们的用户来评注地图和路线，添加新的价值层面。那么对仅仅通过授权使用基础数据来进入这一市场的其他竞争者，将造成远远大得多的困难。
近期Google地图的引入，为应用程序销售商和其数据提供商之间的竞争，提供了一个活生生的实验室。Google的轻量型编程模型已经引发了不计其数的增值服务的出现，这些服务以数据混合的方式，将Google的地图同其他可以通过互联网访问的数据源相结合。保罗·拉特马赫（Paul Rademacher）的housingmaps.com是这种混合的一个上佳范例，其网站将Google的地图同Craigslist的公寓出租，以及住宅购买数据相结合，来创建一种交互式的房屋搜索工具。
目前，这些混合大多是由程序高手们实现的创新性的实验产品。但是企业行动将紧随其后。并且，人们已经可以从至少一类开发者中发现这一点。Google已经将数据源提供者的角色从Navteq那里夺走，并且将自己定位为一个令人喜爱的中介者。在以后几年里，我们将会看到数据提供商和程序销售商之间的斗争，因为两大阵营都认识到了，特定的数据类别在作为搭建Web 2.0程序的积木时是多么的重要。
这场竞赛已经涉及到拥有特定类别的核心数据：位置、身份、公共事件日历、产品标识和命名空间等。在许多情况下，在那些创建数据需要巨额成本的地方，也可能存在一种如同Intel Inside方式一样凭借单一数据源来所有作为的机遇。其他情况下，胜者将是那些通过用户聚合来达到临界规模，并且将聚合的数据融入系统服务中的公司。
比如，在身份标识领域，PayPal，Amazon的一键式，以及拥有数百万用户的交流系统，都有可能成为创建整个网络范围的身份标识数据库的正当竞争者。（关于此，Google最近使用手机号码作为Gmail账号标识的尝试，可能就是朝借鉴和拓展电话系统所迈出的一步。）同时，像Sxip这样的创业公司，正在探索联合身份标识的可能性，以寻求一种“分布一键式”，从而提供一个无缝的Web 2.0标识子系统。在日历领域，EVDB则是通过维基式参与体系来搭建世界上最大的共享日历的一种尝试。虽然评判者尚在观望着任何一个特定创业公司或方式的成功是否，但很显然，这些领域的标准和解决方案，有效地将某些数据转变为“互联网操作系统”（internet operating system）的可靠的子系统，并将促成下一代的应用程序。
关于数据，必须注意一个进一步的方面，那就是用户关心其隐私和对自己的数据的权限。在许多早期的网络程序中，版权只被松散地执行。例如，Amazon宣称对任何提交到其网站的评论的所有权，但却缺少强制性，人们可以将同样的评论转贴到其他任何地方。然而，随着很多公司开始认识到，对数据的掌控有可能成为他们首要的竞争优势来源，我们将会看到在此类控制方面强度更大的尝试。
正如专有软件的增长而导致自由软件运动一样，在下一个10年中我们会看到专有数据库的增长将导致自由数据运动。在像维基百科全书这样的开放数据项目、创作共用（Creative Commons）、以及像Greasemonkey（让用户决定如何在其计算机上显示数据）这样的软件项目中，我们可以看到这种对抗势头的前兆。
| 参与的体系 一些系统被设计为鼓励参与。在丹·布莱克林（Dan Bricklin）的论文“共用的丰饶”（The Cornucopia of the Commons）中，他指出有三种创建大型数据库的方式。第一种，已经由Yahoo!来体现了，就是付费给人们来实现。第二种，由开放源码社区的经验启发而来，就是让志愿者来完成同样的任务。开放目录项目（Open Directory Project），一个Yahoo的开放源码竞争者，就是该方式的产物。但是Napster体现了第三种方式。因为Napster将其默认设置为自动为任何已经下载的音乐服务，任何用户都自动地帮助建立共享数据库的价值。同样的方式已经被其他所有P2P文件共享服务所采用。Web 2.0时代的一个关键经验在于：用户增加价值。但是只有很小一部分用户会有意来为你的程序增加价值，而不怕麻烦。因而，Web 2.0公司均进行了这样的默认设置，即作为程序通常使用方式的副产品，来聚合用户数据并创造价值。正如上面所指出的，他们在搭建那种用户越多则效果越好的系统。 米切尔·卡普尔（Mitch Kapor）曾经指出“体系是策略”。参与是Napster的本质，其根本体系的一部分。 同更经常被引用的所谓“吸引志愿精神”的原因相比，这种体系结构上的洞察力可能更能抓住对开放源码软件成功的本质。互联网、万维网（World Wide Web）、以及像Linux、Apache和Perl这样的开放源码软件项目的体系结构，均是这样一种设计，使得作为一种自动产生的副产品，谋求其自身利益的用户们创建着集体的价值。这些项目中的任何一个都有一个很小的核心、一种设计良好的扩展机制、和一种让任何人来添加任何合乎规定的组件的方式，不断增长着被Perl语言的创始人拉里·沃尔（Larry Wall）称为“洋葱头”（the onion）的外部层面。换句话说，这些技术通过他们本来的设计方式，体现着网络的效应。 |
4. 软件发布周期的终结
如上文在对Google和Netscape的比较中谈到的，互联网时代软件的代表性特征就是它应该被作为服务来交付。这种事实导致这类公司的商业模式上很多根本性的变化。
1. 运营必须成为一种核心竞争力。Google或者Yahoo!在产品开发方面的专门技术，必须同日常运营方面的专门技术相匹配。从软件作为制造品到软件作为服务的变化是如此地根本，以至于软件将不再能完成任务，除非每日加以维护。Google必须持续抓取互联网并更新其索引，持续滤掉链接垃圾和其他影响其结果的东西，持续并且动态地响应数千万异步的用户查询，并同步地将这些查询同上下文相关的广告相匹配。
所以，Google的系统管理、网络、和负载均衡技术，可能比其搜索算法更被严加看管，也就不足为奇了。Google在自动化这些步骤上的成功是其同竞争者相比更有成本优势的一个关键方面。
同样也不足为奇的是，像Perl、Python、PHP、和当前的Ruby这样的脚本语言在Web 2.0公司中扮演着重要角色。Sun公司的第一个网管哈桑·施罗德（Hassan Schroeder）曾对Perl有一个著名的形容：“互联网的管道胶带”（the duct tape of the internet）。事实上，动态语言（常常被称为脚本语言，并被软件制品时代的软件工程师所贬低），是系统和网络管理员，以及创建可经常更新的动态系统的程序开发者们所喜爱的工具。
2. 用户必须被作为共同开发者来对待，这是从对开放源码开发实践的一种反思中得出的（即便所涉及的软件不太可能以开放源码授权方式来发行）。开放源码的格言“早发布并常发布”（release early and release often）事实上已经演变成一种更为极端的定位“永远的测试版”（the perpetual beta）。其中产品在开放状态下开发，新的功能以每月、每周、甚至每天的速度被加入进来。Gmail、Google Maps、Flickr、del.icio.us，和其他类似的服务，可能会在某个阶段打着测试版的标识多年。
故此，实时地监测用户行为，来考察哪些新特性被使用了，以及如何被使用的，将成为另外一种必须的核心竞争力。一位工作于一个主要在线服务网络商的开发者评论道：“我们每天在网站的某些部分提供两到三个新的特性，而且如果用户不采用它们，我们就将其撤掉。如果用户喜欢它们，我们就将其推广到整个网站。”
Flickr的总开发师卡尔·亨德森（Cal Henderson），近来透露了他们是如何在短至每半个小时就部署一个新版本的。显而易见，这是同传统方式有天壤之别的开发模式。虽然不是所有的网络程序都以像Flickr这样的极端方式来开发，但几乎所有网络程序都有一个同任何PC或者客户-服务器时代截然不同的开发周期。正因如此，ZDnet杂志才论断Microsoft不会打败Google：“Microsoft的商业模式依赖于每个人在每两到三年都升级他们的计算环境。Google的模式则依靠任何人每天在其计算环境中自行探索新东西。”
虽然Microsoft已经体现了从竞争中学习并最终做得最好的强大能力，但是毫无疑问这一次的竞争要求Microsoft（可以扩展到任何现存的软件公司）来成为一种在深入层面上显著有别的公司。天生的Web 2.0公司在享受自然而然的优势，因为它们不需要去摆脱陈旧的模式（及其相应的商业模式和营收来源）。
5. 轻量型编程模型
一旦网络服务的观念深入人心，大型公司将以复杂的网络服务堆栈来加入到纷争之中。这种网络服务堆栈被设计用来为分布式程序建立更可靠性的编程环境。
但是，就像互联网成功正是因为它推翻了许多超文本理论一样，RSS以完美的设计来取代简单的实用主义，已经因其简单性而成为大概是应用最广泛的网络服务，而那些复杂的企业网络服务尚未能实现广泛的应用。
类似地，Amazon.com的网络服务有两种形式：一种坚持SOAP(Simple Object Access Protocol，简单对象访问协议）网络服务堆栈的形式主义；另一种则简单地在HTTP协议之外提供XML数据，这在轻量型方式中有时被称为REST（Representational State Transfer，代表性状态传输）。虽然商业价值更高的B2B连接（例如那些在Amazon和一些像ToysRUs这样的零售伙伴之间的连接）使用SOAP堆栈，但是根据Amazon的报道，95%的使用来自于轻量型REST服务。
同样的对简易性的要求，可以从其他“朴实的”网络服务中见到。Google近来的Google地图的推出就是一个例子。Google地图的简单AJAX（Javascript和XML的结合）接口迅速被程序高手们破译，被随即进一步将其数据混合到新的服务之中。
地图相关网络服务已经存在了一段时间，例如像ESRI那样的GIS（地理信息系统），以及从MapQuest和Microsoft的MapPoint。但是Google地图以其简洁性而让世界兴奋起来。虽然从前销售商所支持的网络服务都要求各方之间的正式约定，但Google地图的实现方式使数据可以被捕获，于是程序高手们很快就发现了创造性地重用这些数据的方法。
这里有几条重要的经验：
1. 支持允许松散结合系统的轻量型的编程模型。由企业开发的网络服务堆栈的复杂设计是用来促成紧密结合的。虽然这在许多情况下是必须是，但是许多最重要的应用程序可以事实上保持松散结合，甚至是脆弱的结合。Web 2.0的理念同传统的IT的理念迥然不同。
2. 考虑聚合（syndication）而不是协调（coordination）。简单的网络服务，例如RSS和基于REST的网络服务，是用来向外聚合数据，但并不控制其达到连接的另外一端时发生的事情。这种想法是互联网本身的基础，一种对所谓端到端原则的反映。
3. 可编程性和可混合性设计。像最初的互联网一样，RSS和AJAX这样的系统，都有此共同点：重用的障碍非常低。许多有用的软件事实上是开放源码的，而即便它不是，也没有许多东西来保护其知识产权。互联网浏览器的“查看源文件”选项，使得许多用户可以复制其他任何用户的网页；RSS被设计得使用户能够在需要的时候查看所需要的内容，而不是按照信息提供者的要求；最成功的网络服务，是那些最容易采纳未被服务创建者想到的新的方向。同更普遍的“保留所有权利”（all rights reserved）相比，随着创作共用约定而普及的“保留部分权利”（Some Rights Reserved）一词成为一个有益的指路牌。
装配中的创新
轻量型商业模型是对轻量型编程和轻量型结合的一种自然产物。Web 2.0的理念善于重用。一种像housingmaps.com这样的新服务，是通过将两个现存服务抓取到一起来简单地创建起来的。Housingmaps.com还没有商业模式（目前为止），但对于许多小规模的服务，Google的AdSense（或Amazon的associates fees计划，或者两者都是）为同类服务提供了营收模式。
这些案例为Web 2.0的另外一个关键原则提供了启发，我们将之称为“装配中的创新”。当商品组件充裕时，你可以通过以新颖的或者有效的方式来装配这些组件来创建价值。很像PC革命为硬件商品装配提供了许多创新的机会，其中像Dell这样的公司创造了这种装配的科学，并从而打败了那些商业模式上要求产品开发方面的创新的公司，我们相信Web 2.0为各个公司提供了，通过在利用和整合由其他人提供的服务方面逐渐完善，来赢得竞争的机会。
6. 软件超越单一设备
另外一个值得一提的Web 2.0特性是Web 2.0已经不再局限于PC平台这样一个事实。在对Microsoft的告别建议中，长期的Microsoft开发者戴夫·斯塔兹（Dave Stutz）指出：“超越单一设备而编写的有用软件将在未来很长一段时间里获得更高的利润”。
当然，任何的网络程序都可被视为超越单一设备的软件。毕竟，即便是最简单的互联网程序也涉及至少两台计算机：一个负责网络服务器，而另一个负责浏览器。而且就如我们已经探讨过的，在将网络作为平台的开发中，把这个概念拓展到由多台计算机提供的服务而组成的合成应用程序中。
但是如同Web 2.0的许多领域一样，在那些领域中“2.0版的事物”（2.0-ness）并不是全新的，而是对互联网平台真正潜能的一种更完美的实现，软件超越单一设备这一说法赋予我们为新平台设计程序和服务的关键性的洞察力。
迄今为止，iTunes是这一原则的最佳范例。该程序无缝地从掌上设备延伸到巨大的互联网后台，其中PC扮演着一个本地缓存和控制站点的角色。之前已经有许多将互联网的内容带到便携设备的尝试，但是iPod/iTunes组合却是这类应用中第一个从开始就被设计用于跨越多种设备的。TiVo则是另外一个不错的例子。
iTunes和TiVo也体现了Web 2.0的其他一些核心原则。它们本身都不是网络程序，但都利用了互联网平台的力量，使网络成为其体系中无缝连接的、几乎不可察觉的一部分。数据管理显然是它们所提供的价值的核心。它们也是服务，而非打包的程序（虽然对于iTunes来说，它可以被用作一个打包的程序来仅仅管理用户本地的数据）。不仅如此，TiVo和iTunes都展示了一些集体智慧的方兴未艾的应用。虽然对于每个情况，其实验都是同网络IP入口的周旋。iTunes中只有有限的参与体系，虽然近来增加的播客（podcasting）将这一规则规律性了不少。
这正是我们希望看到伟大变革的Web 2.0领域中的一个，随着越来越多的设备正连接到这个新的平台中来。当我们的电话和汽车虽不消费数据但却报告数据时，可能会出现什么样的程序呢？实时的交通监测、快闪暴走族（flash mobs）、以及公民媒体，只不过是新平台的能力的几个早期警示。
| 一篇Web 2.0的投资论文 风险投资家保罗·科德罗斯基（Paul Kedrosky ）写道：“关键在于去寻找一种你共识相左的，具有可操作性的投资”。有趣的是，我们注意到Web 2.0的每个方面都涉及到同共识的分歧：每个人都在强调保持数据隐私的重要性，而Flickr/Napster等等，却使其公开化。这并非只是为了分歧而分歧（比如追求宠物食在线），而是在可以从中创建出一些东西的地方发生分歧。Flickr缔造了社区，Napster创造了收藏的广度。 另外一种看待这种现象的方式，就是成功的公司都放弃了一些昂贵但被认为重要的东西，以便免费获得一些有价值的曾经昂贵过的东西。例如，维基百科全书放弃了集中的编审控制，以作为对速度和广度的回报。Napster放弃了“目录册”的想法（列出所有销售商正在销售的歌曲），并因此获得了广度。Amazon放弃了用于一个实体店面的想法，却从而服务于整个世界。Google放弃了大宗用户（开始的时候），却得到了80%的，其要求从前未被满足的用户。下面的说法很有一些合气道（借力打力）的精神：“你知道，你是对的——整个世界的人都绝对可以更新这篇文章。而且你猜怎么着，这对你是个坏消息”。 ——内森·托克英顿（Nat Torkington） |
7. 丰富的用户体验
最早可以追溯到1992年魏裴（Pei Wei）开发的Viola浏览器，互联网就被用来在网页浏览器中传送“小程序”（applet）和其他一些活动内容。1995年Java的引入就是围绕着这样的小程序的传送。JavaScript和后来的DHTML都被作为轻量型方式引入，来为客户端提供可编程性和丰富的用户体验。几年以前，Macromedia缔造出“丰富的互联网应用程序”（Rich Internet Applications）一词（该词也被Flash的竞争者开放源码的Laszlo系统使用），以便凸显Flash不仅可传送多媒体内容，而且可以是GUI（图形用户界面）方式的应用程序体验。
然而，互联网传递整个应用程序的潜能在Google引入Gmail之前，一直没有成为主流，紧接着就是Google地图程序，一些基于互联网的带有丰富用户界面以及PC程序等同的交互性的应用程序。在网络设计公司Adaptive Path的耶希•詹姆斯•加莱特（Jesse James Garrett）的一个讨论会论文中，Google所使用的这组技术被命名为AJAX。他写道：
Ajax不是一项技术。它其实是几项技术，每项技术自身都很繁荣，它们以强有力的全新方式结合起来。Ajax涵盖：
-- 运用XHTML和CSS实现基于各种标准的展示。
-- 运用文档对象模型（Document Object Model）实现动态显示和交互。
-- 运用XML和XSLT实现数据交换和操作。
-- 运用XMLHttpRequest实现异步数据检索。
-- JavaScript将所有这些绑定到一起。
AJAX也是Web 2.0程序的一个关键组件，例如现在归属Yahoo!的Flickr，37signals的程序basecamp和backpack，以及其他Google程序，例如Gmail和Orkut。我们正在步入一个史无前例的用户界面创新阶段，因为互联网开发者们终于可以创建，像本地基于PC的应用程序一样丰富的网络程序了。
有趣的是，许多现在正被探索的功能已经存在了很多年了。90年代后期，Microsoft和Netscape，都对现在终于被认识到的那些功能有所洞察，但是它们对于所要采用的标准的争斗，使得实现跨浏览器的应用程序变得困难。仅在当初Microsoft确定无疑地赢得了浏览器之战的时候，而且那时事实上只需要针对一个浏览器标准，编写这种程序才成为可能。同时，虽然Firefox在浏览器市场中重新引入了竞争，但至少在目前我们还没有看到对互联网标准的破坏性的争夺以至于我们倒退到90年代。
在接下来的几年中，我们会看到许多新的网络程序，不仅确实是新颖的程序，而且是对PC程序丰富的网络再现。到目前为止，每个平台的变革也都为改变那些在旧平台中占主导地位的程序的领导地位创造了机会。
Gmail已经在电子邮件中提供了一些有意思的创新，将互联网的力量（随处可访问、深层的数据库能力、可搜索性）与在易用性方面同PC界面接近的用户界面相结合。同时， PC平台上的其他邮件程序，正在从另一端通过增添IM和呈现能力，来蚕食着这一领域。我们离集成通信客户端有多少远呢？这些集成通信客户端应是整合了电子邮件、即时通信和手机，并且应使用VoIP以便向网络程序的丰富功能中添加语音能力。这种竞赛已经开始。
我们也很容易看到Web 2.0是如何重新打造地址簿的。一个Web 2.0风格的地址薄将把PC或电话上的本地地址簿，仅仅当作一种你显式要求系统记忆的联系人的缓存。同时，一个基于互联网的Gmail风格的异步代理，将保存发送或者接收的每个消息，每个电子邮件地址和每个使用过的电话号码，并且创造出社交网络的启发性算法，来决定当一个答案不能在本地缓存中找到时，应该提供哪个作为替代。在缺少答案的情况下，该系统会查询更广阔的社交网络。
一个Web 2.0的字处理程序将会支持维基风格的协作编辑，而不仅仅是处理独立的文档。但是该程序也会支持我们期望在基于PC的字处理器中得到的那种丰富格式。Writely是这种程序的一个优秀范例，虽然它尚未引起广泛关注。
此外，Web 2.0革命不会局限于PC程序。例如，在CRM这样的企业级应用程序中，Salesforce.com展示了网络是如何被用来以服务的方式来传递软件的。
对新的进入者来说，竞争机会在于充分开发Web 2.0的潜能。成功的公司将创建可以向其用户学习的程序，利用可供参与的体系来建立一种决定性的优势，不仅在软件的界面方面，而且在共享数据的丰富程度方面。
Web 2.0公司的核心竞争力
在探索上述七大原则的过程中，我们已经强调了Web 2.0的一些主要特性。我们探讨的每一个例子都体现着这些原则中的一个或多个，但是可能不满足其他的原则。因此，让我们通过总结我们认为是Web 2.0公司核心竞争力的一些方面，来结束本文。
-- 服务，而不是打包的软件，具有高成本效益的可伸缩性。
-- 控制独特的、难以再造的数据源，并且用户越多内容越丰富。
-- 把用户作为共同开发者来信任。
-- 利用集体智慧。
-- 通过客户的自服务来发挥长尾的力量。
-- 软件超越单一设备。
-- 轻量型用户界面、开发模式、和商业模式。
今后一个公司要宣称是“Web 2.0”，就要将其特性同上述列表相测试。越符合就越名副其实。不过要记住，在某一个领域的卓越表现，可能会比对七大原则中的每个都浅尝则止，要更为有效。
| Web 2.0的设计模式 在“模式语言”（A Pattern Language）一书中，克里斯多夫•亚历山大（Christopher Alexander）为精炼描述对于体系结构问题的解决方案，开了一种格式上的处方。他写道：“每个模式都描述着一种在我们的环境中一遍又一遍地出现的问题，并因此描述了对该问题的核心解决方案。以此方式你可以使用该方案上百万次，而从不需要重复作同样的事情。” 1. 长尾 小型网站构成了互联网内容的大部分内容；细分市场构成了互联网的大部分可能的应用程序。所以，利用客户的自服务和算法上的数据管理来延伸到整个互联网，到达边缘而不仅仅是中心，到达长尾而不仅仅是头部。 2. 数据是下一个Intel Inside 应用程序越来越多地由数据驱动。因此：为获得竞争优势，应设法拥有一个独特的，难于再造的数据资源。 3. 用户增添价值 对互联网程序来说，竞争优势的关键在于，用户多大程度上会在你提供的数据中，添加他们自己的数据。因而，不要将你的“参与的体系”局限于软件开发。要让你的用户们隐式和显式地为你的程序增添价值。 4. 默认的网络效应 只有很小一部分用户会不嫌麻烦地为你的程序增添价值。因此：要将默认设置得使聚合用户的数据，成为用户使用程序的副产品。 5. 一些权力保留 知识产权保护限制了重用也阻碍了实验。因而，在好处来自于集体智慧而不是私有约束的时候，应确认采用的门槛要低。遵循现存准则，并以尽可能少的限制来授权。设计程序使之具备可编程性和可混合性。 6. 永远的测试版 当设备和程序连接到互联网时，程序已经不是软件作品了，它们是正在展开的服务。因此，不要将各种新特性都打包到集大成的发布版本中，而应作为普通用户体验的一部分来经常添加这些特性。吸引你的用户来充当实时的测试者，并且记录这些服务以便了解人们是如何使用这些新特性的。 7. 合作，而非控制 Web 2.0的程序是建立在合作性的数据服务网络之上的。因此：提供网络服务界面和内容聚合，并重用其他人的数据服务。支持允许松散结合系统的轻量型编程模型。 8. 软件超越单一设备 PC不再是互联网应用程序的唯一访问设备，而且局限于单一设备的程序的价值小于那些相连接的程序。因此：从一开始就设计你的应用程序，使其集成跨越手持设备，PC机，和互联网服务器的多种服务。 |
奥莱理媒体公司（O'Reilly Media Inc.) 主席兼CEO 提姆·奥莱理（Tim O'Reilly）授权刊登, 美国密西根大学资深软件分析师玄伟剑提供全文翻译。 节略版请参见1121期杂志
- 作者： zhouconghui 2006年07月30日, 星期日 18:02 回复（0） | 引用（0） 加入博采