Because social networking isn't a new idea and people don't care about it enough to switch to a new network anymore. Once upon a time there was Friendster, Ork

Because social networking isn't a new idea and people don't care about it enough to switch to a new network anymore. Once upon a time there was Friendster, Orkut, MySpace, Facebook... Digitizing your connections and friends was a new and exciting concept. Now everyone has been connected and we've seen it's not always a great thing. I don't think it's interesting enough of an experience to replicate rebuilding a network elsewhere at this point.