Web 2.0 Innovation Map
The Web 2.0 Innovation Map is a Google Maps mashup that shows a geographic location for many of the most well-known Web 2.0 applications, including Wikipedia, WordPress, MySpace, Friendster, Flickr, Yahoo!Maps, and Google itself. So, now you can use a Web 2.0 application to learn about other Web 2.0 applications.
Via Digg.com