The program finds all of the movies that you have stored on your hard drive, identifies them, and finds all of their information on IMDB (assuming you are connected to the Internet). Once that's done, it will organize them in its main menu area.
One of its simplest yet most interesting options allows you to filter your movies by whether or not you've seen them with just a click. And since you can also watch your movies from within the app, it's an easy way to watch those movies you've been meaning to see for awhile.
Movie Monkey is a good movie cataloger that helps you organize your collection so that everything is in one place. It's also a great way to learn more about the movies in your collection.