Joshua Porter has written a nice balanced introduction to Web 2.0 on Squidoo.
Meanwhile I'm having a running battle with some idiots on the Wikipedia Web 2.0 page. One or more of these clowns keeps deleting any and all references to my websites and articles. Now I know what Dave Winer feels like when he criticizes Wikipedia. It's a great resource, but just like anything - a few idiots always end up ruining it for the rest of us.