i'm writing a comedy novel about a startup, and one of the running jokes is how much Quora is overhyped. at one point somebody pitching a new idea says "it's like Quora with Badgeville's gamification for the enterprise!" it was supposed to be a joke ... life imitates art, I guess.
As has been mentioned by many people many times before, the problems with shared communication in an enterprise are foremost political, and to some extent legal, much more so than technical.