Facebook was good to keep track of friends but as friends and applications are increasing, I am seeing high noise to signal ratio. I think if Facebook doesn't manage that part it is going to be like Altavista of search. Lots of people used it but they didn't know what they were missing until Google came along. We need something that adds value in peoples lives along with entertainment and socialization. Facebook killer would not be something having more features and something more shiny than facebook but it rethinks how people should socialize. Not just serve as platform for viral marketing and time sinking games.