There's a lot written about such matters, but unfortunately not all of it is worth the volume of cyberspace taken up.

However I've just come across a little gem of presentation on Web 2.0 by Michael Wesch, Assistant Professor of Cultural Anthropology at Kansas State University

It's a short Flash video giving his interpretation of Web 2.0 in just under 5 minutes, or The Machine is Us/ing Us.

This YouTube link is to his final version, as of late February 2007 (turn on your speakers):

But there's more. PLEASE READ ON...