Here you go: http://www.geekshout.com/web-development-seo/what-is-web-2-guide/72
You are right, it's about using Ajax, but not just that. As you can see, there's no list of features that W3C or other consortium agreed with, it's more about common sense on how we can make the future web a better place.
I'm not against web 2.0 or anything, but I'd like to see the websites follow their natural course. I wouldn't want to see digg like websites everywhere. And what frightens me the most is another so called feature of web 2.0: having less graphics in your page. I mean I have a 10 mbps connection, why would I want less graphics then when I had a 256 kbps connection? I like eye-candy!
Bob, I think you'll agree to Paul Boutin:
The new Internet boom doesn't live up to its name: http://www.slate.com/id/2138951/fr/rss/