Every successful StackExchange site has a solid base of users who are revisiting the site on a daily basis.
Puzzling, PCG, they're in for the fun. SFF because they can talk about books/movies they really enjoyed with other people who really enjoyed them. SO because the site's just so helpful to programmers, on so many different occasions.
Health is a one-time hit only. You've just visited your doctor and have a question about something she told you? You visit Health.SE. But that's not the case every second day. This is why we have a low rate of accepted answers: Most users never return. T…