I recently covered Spigit, a complex but very interesting prediction engine and community that's designed to help startups home in on workable ideas and plans. At DemoFall, there's another company like it launching: Virtual Ventures (site not live yet). If you want to play pretend VC, check it out.
Viral Ventures was followed at the DemoFall conference by IdeaBlob, a site where you can share your ideas with the crowd to win prizes. Reminds me of those matchbook and comic book ads: "Are you an inventor?"
I like prediction engines, and certainly crowds can be smart. But I think that if companies start to rely on games to vet their business models, they're asking for trouble. Wisdom of the crowds? Sure, I'll listen, but mobs don't build iPods.