Web 2.0

Web 2.0, a phrase coined by O'Reilly Media in 2004,refers to a perceived or proposed second generation of Web-based services—such as social networking sites, wikis, communication tools, and folksonomies—that emphasize online collaboration and sharing among users. O'Reilly Media, in collaboration with Medialive International, used the phrase as a title for a series of conferences, and since 2004 some developers and marketers have adopted the catch-phrase. Its exact meaning remains open to debate, and some technology experts, notably Tim Berners Lee, have questioned whether the term has meaning.

The last, compact definition of Web 2.0, according to Tim O'Reilly is this one:

"Web 2.0 is the business revolution in the computer industry caused by the move to the internet as platform, and an attempt to understand the rules for success on that new platform. Chief among those rules is this: Build applications that harness network effects to get better the more people use them.".

Instruction

Alluding to the version-numbers that commonly designate software upgrades, the phrase "Web 2.0" hints at an improved form of the World Wide Web; and advocates suggest that technologies such as weblogs, social bookmarking, wikis, podcasts, RSS feeds (and other forms of many-to-many publishing), social software, Web APIs, Web standards and online Web services imply a significant change in web usage.

Time bar of Web 2.0 buzz words.[4] This image shows the age of some buzzwords sometimes used in Web 2.0 lingo and its dependencies.

As used by its proponents, the phrase "Web 2.0" can also refer to one or more of the following:

• The transition of websites from isolated information silos to sources of content and functionality, thus becoming computing platforms serving web applications to end-users
• A social phenomenon embracing an approach to generating and distributing Web content itself, characterized by open communication, decentralization of authority, freedom to share and re-use, and "the market as a conversation"
• Enhanced organization and categorization of content, emphasizing deeplinking
• A rise or fall in the economic value of the Web, possibly surpassing the impact of the dot-com boom of the late 1990s

Earlier users of the phrase "Web 2.0" employed it as a synonym for "Semantic Web," and indeed, the two concepts complement each other. The combination of social-networking systems such as FOAF and XFN with the development of tag-based folksonomies, delivered through blogs and wikis, sets up a basis for a semantic web environment.

In the opening talk of the first Web 2.0 conference, Tim O'Reilly and John Battelle summarized key principles of Web 2.0 applications:

• the web as a platform
• data as the driving force
• network effects created by an architecture of participation
• innovation in assembly of systems and sites composed by pulling together features from distributed, independent developers (a kind of "open source" development)
• lightweight business models enabled by content and service syndication
• the end of the software adoption cycle ("the perpetual beta")
• software above the level of a single device, leveraging the power of The Long Tail.
• easy to pick up by early adopters

On September 30, 2005, Tim O'Reilly wrote a piece summarizing the subject. The mind-map pictured above (constructed by Markus Angermeier on November 11, 2005) sums up the memes of Web 2.0, with example-sites and services attached.:

Tim O'Reilly gave examples of companies or products that embody these principles in his description of his "four plus one" levels in the hierarchy of Web 2.0-ness:

• Level 3 applications, the most "Web 2.0", which could only exist on the Internet, deriving their power from the human connections and network effects Web 2.0 makes possible, and growing in effectiveness the more people use them. O'Reilly gives as examples: eBay, craigslist, Wikipedia, del.icio.us, Skype, dodgeball, and Adsense.
• Level 2 applications, which can operate offline but which gain advantages from going online. O'Reilly cited Flickr, which benefits from its shared photo-database and from its community-generated tag database.
• Level 1 applications, also available offline but which gain features online. O'Reilly pointed to Writely (since 10 October 2006: Google Docs & Spreadsheets, offering group-editing capability online) and iTunes (because of its music-store portion).
• Level 0 applications would work as well offline. O'Reilly gave the examples of Mapquest, Yahoo! Local, and Google Maps. Mapping applications using contributions from users to advantage can rank as level 2.
• non-web applications like email, instant-messaging clients and the telephone.

Characteristics of "Web 2.0"

While interested parties continue to debate the definition of a Web 2.0 application, a Web 2.0 web-site may exhibit some basic characteristics. These might include:

• "Network as platform" — delivering (and allowing users to use) applications entirely through a browser. See also Web operating system.
• Users owning the data on the site and exercising control over that data.
• An architecture of participation and democracy that encourages users to add value to the application as they use it.This is a sharp contrast to hierarchical access control in applications, in which users are categorized into roles with varying levels of functionality.
• A rich, interactive, user-friendly interface based on Ajax or similar frameworks. *Some social-networking aspects.
• a Public good. "public goods" are characterized by two properties: jointness of supply and non-excludability (Hardin, 1982. The impossibility to exclude group members who didn’t contribute to the provision of goods from sharing its profits gives rise to the possibility that rational members will prefer to withhold their contribution of effort and "free ride" (see Free rider problem) on contribution of others (Marwell and Ames, 1979. (see web 2.0 as public good)

The concept of Web-as-participation-platform captures many of these characteristics. Bart Decrem, founder and former CEO of Flock calls Web 2.0 the "participatory Web" and regards Web-as-information-source as Web 1.0.

Technology overview

The complex and evolving technology infrastructure of Web 2.0 includes server-software, content-syndication, messaging-protocols, standards-based browsers with plugins and extensions, and various client-applications. These differing but complementary approaches provide Web 2.0 with information-storage, creation, and dissemination capabilities that go beyond what the public formerly expected of web-sites.

A Web 2.0 website may typically feature a number of the following techniques:

• Rich Internet application techniques, optionally Ajax-based
• CSS
• Semantically valid XHTML markup and the use of Microformats
• Syndication and aggregation of data in RSS/Atom
• Clean and meaningful URLs
• Extensive use of folksonomies (in the form of tags or tagclouds, for example)
• Use of wiki software either completely or partially (where partial use may grow to become the complete platform for the site)
• Weblog publishing
• Mashups
• REST or XML Webservice APIs

Criticism

Given the lack of set standards as to what "Web 2.0" actually means, implies, or requires, the term can mean radically different things to different people.

Many of the ideas of Web 2.0 already featured on networked systems well before the term "Web 2.0" emerged. Amazon.com, for instance, has allowed users to write reviews and consumer guides since its launch in 1995, in a form of self-publishing. Amazon also opened its API to outside developers in 2002. Prior art also comes from research in computer-supported collaborative learning and computer-supported cooperative work and from established products like Lotus Notes and Lotus Domino.

Conversely, when a web-site proclaims itself "Web 2.0" for the use of some trivial feature (such as blogs or gradient boxes) observers may generally consider it more an attempt at self-promotion than an actual endorsement of the ideas behind Web 2.0. "Web 2.0" in such circumstances has sometimes sunk simply to the status of a marketing buzzword, like "synergy", that can mean whatever a salesperson wants it to mean, with little connection to most of the worthy but (currently) unrelated ideas originally brought together under the "Web 2.0" banner. The argument also exists that "Web 2.0" does not represent a new version of World Wide Web at all, but merely continues to use "Web 1.0" technologies and concepts.

Other criticism has included the term "a second bubble", (referring to the Dot-com bubble of circa 1995–2001), suggesting that too many Web 2.0 companies attempt to develop the same product with a lack of business models. The Economist has written of "Bubble 2.0".

Venture capitalist Josh Kopelman noted that Web 2.0 excited only 53,651 people (the then number of subscribers to TechCrunch^?, a Weblog covering Web 2.0 matters), too few users to make them an economically-viable target for consumer applications.

See also

• Crowdsourcing
• Library 2.0
• Mashups
• Office 2.0
• Service-oriented architecture
• Social bookmarking
• Social computing
• Web operating system
• Enterprise 2.0
• Wikipedia

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