For the newcomers so used to being pigeonholed they think they must pigeonhole themselves, there is this:

http://en.rocketnews24.com/2014/04/21/better-know-a-train-nerd-36-different-classifications-for-japans-densha-otaku

>>	Kartma!wvTgDQHyaM Sat Jan 2 08:51:23 2016 No.131115   File: 1451746283810.jpg -(87395 B, 325x215) Thumbnail displayed, click image for full size. So many specialties.