A hardcore/obsessed fan of a band that posts on message boards, scours the internet for the newest info, buys their merchandise/music, attends the majority (if not all) of the band's gigs, etc., but is not a stalker or performs sexual favors like a groupie. About as close to a band as a roadie, but not.
An obsessed audiophile with some self-respect.
"Did you know that The Killer's new cd just came out?"
"Yeah, I just bought it the other day. You should read the Q article. It just went up 5 minutes ago on the forum."
"Are you stalking them or you just wanna get in their pants?"
"No dude, I'm just a broupie."