Jobs of the future, #1: Online Community Organizer

Seth Godin suggests that an up-and-coming job description will be Online Community Organizer; that would be someone who can gather together everyone in an industry and make them feel like they have to be part of the conversation in this forum. I could see it coming someday, but my feeling right now is that all of the successful online communities are happening more or less by accident. Facebook, MySpace, Twitter. What makes Twitter a more dynamic online community than Pownce? Not much, I hear; maybe some sort of first- or second-mover advantage? But is there really somebody out there capable of moving from one job of this type to another and being successful at both? I have my doubts.