Define: Web 3.0, Web 2.0, Web 1.0
Web 1.0: Companies publish content that people consume (e.g. CNN)
Web 2.0: People publish content that other people can consume, companies build platforms that let people publish content for other people (e.g. Flickr, YouTube, Adsense, Wikipedia, Blogger, MySpace, RSS, Digg)
Web 3.0: People build applications that other people can interact with, companies build platforms that let people publish services by leveraging the associations between people or special content (e.g. FaceBook, Google Maps, My Yahoo!)
— amr