www.lucidrealms.com

While I'm typically not very fond of social networks I have to say that I do think that www.ohloh.net is pretty cool. Perhaps I like it so much not because of the "social network" part, but because it gives you a quick glimpse into the development of open source projects. It is interesting to see who and how many people have contributed to a project, or just how many lines of code there are. If you know what you are doing you could find all of this information yourself but it is nice having it easily available. I think the whole Kudos/ranking thing is a little silly and meaningless, but whatever. It is also kind of cool that they essentially build up an open source resume for you (yeah I know mine is currently pretty sad).