Since it came out in 1988, Beetlejuice has been building a small, yet devoted fandom. Hey, you don't make $73 million dollars in movie theaters and not have a few people remember your movie.
First, there's your devoted fansites. The Beetlejuice Wiki shares exhaustive articles about the movie. The Neitherworld has details about the Beetlejuice cartoon series that ran from 1989-1991. And there's a group of fans that are in the process of making a Beetlejuice-inspired documentary about the making of the movie. You can check their site—The Documentary for the Recently Deceased—for more details.