People flipped for Ghostbusters when it came out. It was popular with kids, teenagers, parents, grandparents... well, some grandparents. Basically, the fandom consisted of almost everyone in America and anywhere in the world that had a movie screens.
Kids were their favorite buster for Halloween, people got the characters' faces tattooed on their bodies, and one lady even convinced Ernie Hudson to give her away at her wedding while in costume as Winston Zeddemore. We're seriously not making this stuff up.
Sure, the Ghostbuster fever has died down these days, since the movie did come out over 30 years ago, and (let's face it) the sequel didn't quite measure up to the original. But that doesn't stop a faithful cult following from maintaining tons of fansites. Like this one. Or this one. Oh, and don't forget the Ghostbusters fanfic. (Watch out; some of that fan fic is pretty steamy.)
We could keep linking out to websites, but you probably get the point. Ghostbusters was a major hit in the 80's, and now it's a cult classic. You're not going to see as many Ghostbusters as you do Klingons at Comic Con, but you will see a few proton packs in the convention center. Now the question on every fan's mind is, "Will Ghostbusters III reboot things?"