Much of the power of SO comes from twin occurrences: 1) Most answers are well indexed on Google. 2) They are right often enough that seeing SO in the search r

Much of the power of SO comes from twin occurrences: 1) Most answers are well indexed on Google. 2) They are right often enough that seeing SO in the search results generates a click over other options. The net is a very high brand value. Hard to monetize by putting up a pay wall and hard to beat too. Network effects suggest that one service with a million users beats ten with 100 thousand each.