Robert "fourzerotwo" Bowling tossed up a link to a new page on the Infinity Ward site devoted to user-responses to an IW-posed question. Billing it as a test, they're currently looking for things you'd like to see appear in Call of Duty: Modern Warfare 2.
So far, the thing that seems to keep scrolling through the results page is "co-op" but a lot of people are getting specific with desires for silencers on sniper rifles, 48-player support, and the return of Captain Price. It's kind of interesting to watch the demands flow throw in real-time, and you can vote individual comments up and down as they roll through.