Observing Quora's success I'd say it's a combo of two things: a) Game mechanics to drive participation. b) Ability for contributors to be moderated by their p

Observing Quora's success I'd say it's a combo of two things: a) Game mechanics to drive participation. b) Ability for contributors to be moderated by their peers in a simpler (lazier) fashion than your typical Wiki which is less transparent,