While not massively into it, I like it enough to have signed up to the fan club and every now and then I'll read the set of books, watch all the movies and then find out some obscure things about various people.
JK writes a lot of the stuff on the fan club and is sort of expanding and refining the extended universe.
Any other fans? If so there are questions apparently designed by JK to determine house, wand type and patronus.
https://my.pottermore.com/user-profileNot sure if you can see mine from there but I got Syltherin, Ebony wood Dragon heartstring and Ibizan Hound.