I had (have) a myspace page, but I haven't updated it since 2007. Never really got into it and just did it because everyone else was. Facebook I was addicted to when I first signed up, then I sort of stopped paying attention to it and now I check it maybe once a week. I haven't wrote anything on my wall in months. Twitter is nonsensical to me.
There are way too many of these damn social network sites now. Myspace, Facebook, Twitter, Digg, Tagged. People don't even bother with personal webpages anymore. Now it's all about things that have a a "friends" list.