Like eating in a restaurant, like dancing at a wedding, like hitting the hors d’ouvres at a party, using social media sites is easier when others blaze the trail. The "empty restaurant" makes you, as a potential patron, wonder if no one else is eating here, is that an indication that I shouldn't either? In social media terms, if there's no one else using this service, perhaps I shouldn't waste my time on it either. iTunes Ping and the Apple Game Center are prime examples. Jay Goldman explains some of the problems facing a social media start-up, even a start-up with big budget backing like Ping and Apple's Game Center.