Dare says that "Web 2.0" is meaningless hype, and quotes Joel Spolsky, who has a good post out on the same topic. Here's Dare's summary:

I feel the same way. I am interested in discussions on the Web as a platform and even folksonomies (not tagging) but the marketplace of ideas has been polluted by all this "Web 2.0" garbage. Once again, I've flipped the bozo bit on Web 2.0. Like Joel, you won't see any use of the term on my blog or in items I link to from now on.

I think they are both dead on target with this. There's a lot of buzzword bingo going on, and it looks like people are starting to spend money stupidly again.