I LOVE reading Science Fiction, have thousands of books, consider myself a SF nerd, but don't post or read SF forums, have no interest.
Also reggae music,
For these two, I read it, thats enough and I listen to it, thats enough.
But my other loves.
HORROR/EXPLOITATION/ETC FILMS - I write and read forums.
Vegetarian/Vegan cooking/food - I write and read.
Posters of course.