Four years on from the first serious attempt to define Web 2.0, there is no firm consensus about what constitutes Web 2.0.
Companies identified by analysts such as Forrester and Gartner as eager to harness Web 2.0 seem to be less interested in technology, than the potential of Web 2.0 "social networking" phenomena, modeled on Facebook and its peers, to improve collaboration within the company, and to encourage customers to give up information about themselves, and feedback about products and services. For some businesses though this provides as much concern as opportunity.
But other companies, facing an expected cut in IT budgets, are excited by the prospects of equipping end-users with the power to write their own applications with freely-downloadable tools and components.
Inventor of the World Wide Web Tim Berners-Lee has said that some of the supposedly defining characteristics of Web 2.0, such as collaboration and user involvement, are what the web was supposed to be about all along. He has pointed out, as others have, that Amazon was incorporating user-generated content (book reviews began in 1996) and Rest (Representational State Transfer) in its developments long before the term Web 2.0 came into use. So in effect, we are simply at a later stage of Web 1.0.
Meanwhile the dawn of Web 3.0 is already being proclaimed by excitable technology columnists, marketing people clutching at the next big thing, and developers who want the Web 2.0 brand buried.
In 2005, respected developers' handbook publisher Tim O'Reilly set down in detail what separated Web 1.0 from Web 2.0.
Further reading - more ComputerWeekly articles on Web 2.0