What's interesting, beyond this, is the kinds of AUs that you see in each fandom. In QAF, you're more likely to see age-inversion fics (Justin older than Brian, Brian back in high school) or disability fics (Justin the artist, now blind). Perhaps I never found it, but you don't see a lot of outer space, or circuses, or the Middle East with that fandom. Which sort of begs the question, why are some AU settings more likely to turn up in one fandom than another?