Supports the website mostly which runs all the free competitions for the community, sets up paid competitions like the Monthly Finals for $500. These can be entered for free if you win free competitions or you can always pay $10 per person entry. You also get exclusive access to Premium tournaments which I believe will return next cod. "Stand out in the forums with huge forum signatures, avatars and yellow background!"
EDIT: You can activate a free one week premium as well, every account gets this to begin with.