Used to describe 1) a failed Web 2.0 company or 2) a poor implementation of a successful Web 2.0 service
1) That Web 2.D'oh! company provided a calendar that you can share. Like we really needed another one of those. Sorry but a glossy logo can't turn a bad idea into a goldmine.
2) Did you see that company added a twitter feed to their site? Talk about a Web 2.D'oh! implementation. The only people following it are the other employees and that's probably because they are forced to.