I'm sure stuff like this will cause another privacy stir, but you can get a geographical map of your friend network on Orkut. - Here's mine (red is friend, blue is friend-of-friend)
My map points how my Boston and Virginia friends aren't really represented at all; just a big gob of people in SF. Although it would be nice for these to fill in, the fact is that orkut has become rather boring, and I sign in about once a month nowadays (the same with Friendster).
meta points to dodgeball as an example of social network service that has some potential. Dodgeball lets you use SMS to announce to your social network where you currently are, which is nice at night when you're bar hopping. Having seen it in action, though, I'm willing to bet that it will go the way of the dodo; it's simply too annoying to be receiving text messages all the time and it's not clear to me that a cellphone has a rich enough of a UI to make it not annoying.
(via joi ito)