Web 2.0 – A Definition

Web 2.0 is defined as an online application that uses the World Wide Web (www) as a platform and allows for participatory involvement, collaboration, and interactions among users. Web 2.0 is also characterized by the creation and sharing of intellectual and social resources by end users. Examples of Web 2.0 applications are web logs or “blogs”; online diaries that allow the originator and readers to state ideas and react; WIKIS (e.g., Wikipedia), which are topical collections of information that can be edited by multiple individuals within a group; and social networking sites (e.g., Facebook) where users can create personalized pages of information and interact with others.
http://www.cosn.org/Portals/7/docs/Web%202.0/CoSN%20Report%20042809Final%20w-cover.pdf