Letterboxd - Letterboxd is a social site for sharing your taste in film, now in public beta.
Delicious Library - Delicious Library 3: Catalog your books, movies, music, software, toys, tools, electronics, & video games. Archive your life.
IMDb - Internet Movie Database
Filmotech - Filmotech is a movie catalog software for movies on DVD, Blu-ray, DivX, CD, VHS and more.
Simkl - Simkl is a TV, anime, and movie tracker that keeps a history of all the shows and movies you watch in one, central location. It’s a mobile app, a website, Google Chrome extension to keep track of everything you watch and integrates with many TV apps
Trakt.tv - Automatically track TV shows & movies you're watching.