Tim O'Reilly attempts to clarify just what is meant by Web 2.0, the term first coined at a conference brainstorming session between O'Reilly Media and MediaLive International, which also spawned the Web 2.0 Conference.
C. Marlow, M. Naaman, D. Boyd, and M. Davis. HYPERTEXT '06: Proceedings of the seventeenth conference on Hypertext and hypermedia, page 31--40. New York, NY, USA, ACM, (2006)