How can I keep track of the movies and documentaries I have seen?

I would like to keep track of the movies and documentaries I have watched – by episodes if it is a series.

I recently discovered www.goodreads.com that provides a similar service for books.

Do you know if any site that will let me track movies?

Optionally, I would like to get involved in discussions about those documentaries with other viewers, or look at similar documentaries, recommendations and reviews by other people, etc.

Thanks!