This illustration was created in early 2006 using logos of Web 2.0 companies that made headlines or were launched around that time. Obviously, lot of things changed in the last three years - some companies got acquired, some became successful on their own while others went bust.
This shift in the way we consume information has been brilliantly captured in these graphs by Thomas Baekdal who also predicts that traditional media reporting on newspapers, Television & Radio will disappear by 2020 to be replaced by social news.
Tim O'Reilly, the founder of O'Reilly Media, has written a colored and illustrated PDF book on Twitter called The Twitter Book. The title, available as an ebook and hard cover, promises to teach you everything you need to know to quickly become a Twitter power user.