The idea is basically to have a simple goal of how many movies you aim to check (similar to the reading goal on Goodreads). This could be on a yearly or monthly basis.

I think the idea should be as simple as possible, but you could make it more customizable, too. I'd say you should only include feature films, but you could allow yourself other types. Or you could make it "in <x official lists" or something similar.

In any case, it works well for books and would presumably be a relatively small feature to introduce.