Web 2.0 is a term often applied to a perceived ongoing transition of the World Wide Web from a collection of websites to a full-fledged computing platform serving web applications to end users. Ultimately Web 2.0 services are expected to replace desktop computing applications for many purposes.
Everyone has a different thought about web2.0 but here is what I think it's boiled down to. A flashy logo with usually a reflection, ajax and javascript galore, rounded corners and that's about it lol.
To explain web 2.0 watch this YouTube video that everybody seems to be watching: http://www.youtube.com/watch?v=6gmP4nk0EOE&mode=related&search=
heh online video viewing, video converting, proxies, zip extractors, etc etc, replacing current desktop apps
This is the best summary of Web 2.0 I've read: you make the content, we make the money! In other words, users are expected to generate the pictures (Flickr), videos (YouTube), and random angst-ridden ramblings (MySpace), while the site owners generate the ad revenue from them.
Yes, quite - it's a quote like this that should be put all over the web It would burst a few utopian theorists egos.