[7]
The Web we know now, which loads into a browser window in essentially static screenfuls, is only an embryo of the Web to come. The first glimmerings of Web 2.0 are beginning to appear, and we are just starting to see how that embryo might develop. The Web will be understood not as screenfuls of text and graphics but as a transport mechanism, the ether through which interactivity happens. It will [...] appear on your computer screen, [...] on your TV set [...] your car dashboard [...] your cell phone [...] hand-held game machines [...] maybe even your microwave oven.
Writing when Palm Inc. was introducing its first web-capable personal digital assistant, supporting web access with WAP, DiNucci saw the web "fragmenting" into a future that extended far beyond the browser/PC combination it was identified with. Her vision of the web's future focused on how the basic information structure and hyperlinking mechanism introduced by HTTP would be used by a variety of devices and platforms. As such, her use of the "2.0" designation refers to a next version of the web that does not directly relate to the term's current use.
The term Web 2.0 did not resurface until 2002.[8][9][10][11] These authors focus on the concepts currently associated with the term where, as Scott Dietzen puts it, "the Web becomes a universal, standards-based integration platform".[10] John Robb wrote: "What is Web 2.0? It is a system that breaks with the old model of centralized Web sites and moves the power of the Web/Internet to the desktop."[11]
In 2004, the term began its rise in popularity when O'Reilly Media and MediaLive hosted the first Web 2.0 conference. In their opening remarks, John Battelle and Tim O'Reilly outlined their definition of the "Web as Platform", where software applications are built upon the Web as opposed to upon the desktop. The unique aspect of this migration, they argued, is that "customers are building your business for you".[12] They argued that the activities of users generating content (in the form of ideas, text, videos, or pictures) could be "harnessed" to create value. O'Reilly and Battelle contrasted Web 2.0 with what they called "Web 1.0". They associated Web 1.0 with the business models of Netscape and the Encyclopædia Britannica Online. For example,
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.[13]
In short, Netscape focused on creating software, updating it on occasion, and distributing it to the end users. O'Reilly contrasted this with Google, a company that did not at the time focus on producing software, such as a browser, but instead on providing a service based on data such as the links Web page authors make between sites. Google exploits this user-generated content to offer Web search based on reputation through its "PageRank" algorithm. Unlike software, which undergoes scheduled releases, such services are constantly updated, a process called "the perpetual beta". A similar difference can be seen between the Encyclopædia Britannica Online and Wikipedia: while the Britannica relies upon experts to create articles and releases them periodically in publications, Wikipedia relies on trust in anonymous users to constantly and quickly build content. Wikipedia is not based on expertise but rather an adaptation of the open source software adage "given enough eyeballs, all bugs are shallow", and it produces and updates articles constantly. O'Reilly's Web 2.0 conferences have been held every year since 2004, attracting entrepreneurs, large companies, and technology reporters.
The term Web 2.0 was initially championed by bloggers and by technology journalists, culminating in the 2006 TIME magazine Person of The Year (You).[14] That is, TIME selected the masses of users who were participating in content creation on social networks, blogs, wikis, and media sharing sites. In the cover story, Lev Grossman explains:
It's a story about community and collaboration on a scale never seen before. It's about the cosmic compendium of knowledge Wikipedia and the million-channel people's network YouTube and the online metropolis MySpace. It's about the many wresting power from the few and helping one another for nothing and how that will not only change the world but also change the way the world changes.
Characteristics

A list of ways that people can volunteer to improve Mass Effect Wiki, an example of content generated by users working collaboratively.

Edit box interface through which anyone could edit a Wikipedia article.
Web 2.0 websites allow users to do more than just retrieve information. By increasing what was already possible in "Web 1.0", they provide the user with more user-interface, software and storage facilities, all through their browser. This has been called "network as platform" computing.[2] Major features of Web 2.0 include social networking sites, user created web sites, self-publishing platforms, tagging, and social bookmarking. Users can provide the data that is on a Web 2.0 site and exercise some control over that data.[2][15] These sites may have an "architecture of participation" that encourages users to add value to the application as they use it.[1][2] Some scholars have put forth cloud computing as an example of Web 2.0 because cloud computing is simply an implication of computing on the Internet.[16]
The concept of Web-as-participation-platform captures many of these characteristics. Bart Decrem, a founder and former CEO of Flock, calls Web 2.0 the "participatory Web"[17] and regards the Web-as-information-source as Web 1.0.
Web 2.0 offers all users the same freedom to contribute. While this opens the possibility for serious debate and collaboration, it also increases the incidence of "spamming" and "trolling" by unscrupulous or misanthropic users. The impossibility of excluding group members who don’t contribute to the provision of goods from sharing profits gives rise to the possibility that serious members will prefer to withhold their contribution of effort and free ride on the contribution of others.[18] This requires what is sometimes called radical trust by the management of the website. According to Best,[19] the characteristics of Web 2.0 are: rich user experience, user participation, dynamic content, metadata, web standards and scalability. Further characteristics, such as openness, freedom[20] and collective intelligence[21] by way of user participation, can also be viewed as essential attributes of Web 2.0.