A phrase connoting a cumulative change in the nature of the Web, characterized by an increase in the ability of Web-based applications to share data and services and by the lowering of the barriers to Web users participating in the creation of the Web's content (blogs, videos, etc.). The phrase was popularized by Tim O'Reilly, the technical publisher.

The second phase of architecture and application development for the web. Web 2.0 applications often use a combination of techniques devised in the late 1990s, including public web service APIs (dating from 1998), Ajax (1998), and web syndication (1997). They often allow for mass publishing (web-based social software). The term may include blogs and wikis. To some extent Web 2.0 has become a buzzword, incorporating whatever is newly popular on the Web (such as tags and podcasts). A consensus on its exact meaning has not yet been reached. Proponents of the Web 2.0 approach believe that Web usage is increasingly oriented toward interaction and rudimentary social networks, which can serve content that exploits network effects with or without creating a visual, interactive web page.

Web 2.0 is an evolving term, which describes a group of improvements to the World Wide Web. In general, the enhancements are working to enhance collaboration and the sharing of information. Blogging is an advancing example that may facilitate collaborative and sharing potential of Web 2.0. Blogging is, at times, a collaborative project undertaken by a team of individuals. Publishing and sharing postings on a particular topic is made simple by Web syndication feeds.

"Web 2.0 is the network as platform, spanning all connected devices; Web 2.0 applications are those that make the most of the intrinsic advantages of that platform: delivering software as a continually-updated service that gets better the more people use it, consuming and remixing data from multiple sources, including individual users, while providing their own data and services in a form that allows remixing by others, creating network effects through an "architecture of participation," and going beyond the page metaphor of Web 1.0 to deliver rich user experiences." (from Tim O'Reilly.)