iTunes is the top seller of downloadable movies, controlling two thirds of the total market, according to IHS Screen Digest. This proud distinction is focused on the actual purchase of movies from iTunes, not streaming internet rentals (such as those offered by Netflix). IHS is a market research firm that analyzes streaming video and the electronic sales of movies, which makes this kind of study their exact bailiwick.
The closest runner up to Apple's success was Microsoft, who only sold a quarter of the movies that Apple did. If you add up all the non-Apple online retail outlets for electronic movies, they make up a little more than one third of the available sales. Of course, selling movies online is a relatively new business, and things could change in 2011. In the meantime, it seems if you want to sell a movie online, you really need to be on iTunes.