What is Web 2.0? All you need to know.

Web 2.0 described in 3min by Silicon Valley's Tim O'Reilly, Tony Perkins, Scott Millner, Aaron Cohen, Chris Alden, Andrew Keen, Michael Tanne, Jonathan Abram, Eric Shcmidt, Joe Kraus, Michael Arrington, Guy Kawasaki, Guatam Gadhwani