When Game Center was first announced way back in April, the first question everyone had was about all of the third-party networks that had already built up in the space. OpenFeint was the biggest of these, and founder Jason Citron had no apparent worries about Apple's advance into social gaming -- he said that OpenFeint would continue to offer features beyond what Game Center did, and that developers would be easily able to use both networks in their apps. A report released last week by OpenFeint says that's exactly what's happened -- the userbase has doubled to a whopping 50 million users since Game Center launche
