Another data point - I don't read or write fanfic. I don't disapprove of it, I just have no interest in it. I don't mind shared universe writing, but I consider it more useful in the sense of having a pre-built scenario, or of exploring more options, than of revisiting familiar characters.

And I might just be very slightly prone to Asperger's. Science-based rather than Humanities? Check. Programmer? Check.