Web 2.0. La rivoluzione siamo noi

The article explores the technical and social features of the evolution from Web 1.0 to Web 2.0, starting from the assumption that Web 2.0 is not a revolution but a simple evolution of the World Wide Web. Various services of Web 2.0 are presented with the history of their development, technical and social aspects, and their use in libraries. Therefore blogs, feed RSS, wikis, social bookmarking, social referencing, media sharing services, social nwtworks, podcasts, multi-user virtual environment are all discussed in the article. Finally, folksonomies and the long tail are explored, as well as other crucial aspects, as referred to the organization of library 2.