For answerers: there's the monetary incentive. For questioners: you pay the money upfront, when you post the question. Once you have the answers, since you've

For answerers: there's the monetary incentive. For questioners: you pay the money upfront, when you post the question. Once you have the answers, since you've already paid, psychologically speaking, it's going to be more difficult to stiff the answerer, since you've already accomplished the act of paying and you've already "mentally" parted with the money. Obviously plenty of people _will_ try to game the system, and it's based on the premise that "people are basically good." That was the premise behind eBay, and they still built a pretty good business out of it. Plenty of people try to game the system, but still the vast majority of transactions go off without a hitch, and it's a multibillion dollar business.