I can't keep up with all the social networking websites out there.
it's not really a full fledged social networking site as much as it is a feature. I mean, I don't ever go to the twitter.com website...
I have a little desktop app that displays all of my friends updates. The updates I submit go straight to facebook etc... and you can send updates via your phone or the desktop app etc... It's a little creepy, but like I said my Dad got me into it and it's worked pretty well for staying up to date on him.
Between texting, IM, email, the board, Facebook, myspace, last.fm and XBox live - I already have way too clear an idea of what everyone is doing all the time. I don't know that life was meant for this kind of over documentation.