The Stack Overflow guys seem to be building a healthy, if modest, business around Q&A based on an advertising + services (job boards, etc) model. Granted, I'm n

The Stack Overflow guys seem to be building a healthy, if modest, business around Q&A based on an advertising + services (job boards, etc) model. Granted, I'm not sure this could grow into a billion dollar business, but it may be profitable. It also seems that Quora is aiming squarely at Stack Exchange, and both companies seem to be holding their long-term strategies close to their chest. Perhaps they see some monetization strategy that the rest of us are failing to grasp?