Fan

From Fandom wank wiki

Short for "fanatic," a fan is someone who is really into something. And isn't afraid to tell you about it. And often thinks that the fact of being a fan means s/h/it is "better" than people who are not fans. (Whether this is true or not is not the point. Most of the time.)

Fans are prone to in-jokes* and obsessive behavior, and many are batshit insane -- but who isn't? No matter what, though, you'll never be a True Fan.

A group of fans of a thing is called a fandom. Fandoms wank. And that's why we're here.

*(The fannish plural of fan is fen. This should tell you a lot.)