IW spokesman Rob Bowling claims 2,500 Steam accounts have already been banned for cheating.
Valve has responded to the boycott other digital distributors have announced on Steamworks games.
Alienware PCs are now shipping with Steam pre-installed and a free copy of Portal.
Stardock reckons that Valve has at least 70 percent of the digital distribution market cornered.
Jesse Stern, Modern Warfare 2's scriptwriter, has talked about That Level.
Valve has revealed how digital distribution is shaking up the industry in terms of online sales and pricing.
All Xbox 360 and PS3 copies of Call of Duty: Modern Warfare 2 have been recalled in Russia because of objections to the airport scene.
Activision has been hinting at subscription fees and micro-transactions for future Call of Duty games.
Modern Warfare 2 is here and it's bigger and more controversial than we thought possible. It's so huge in fact that Joe and Harry have teamed up to tackle it. Is the singleplayer more than endlessly respawning troops and is IWNet as bad as it sounds?
The street date for Modern Warfare 2 has been smashed by some retailers and a pricing war has broken out.
Activision president Mike Griffith has spoken out in defence of the PC version of Modern Warfare 2.
Infinity Ward has announced that the maximum players in the PC version of Modern Warfare 2 has been heavily reduced.
Infinity Ward has confirmed a third person view option in Call of Duty: Modern Warfare.
Activision has finally released the official PC requirements for Call of Duty: Modern Warfare 2.
Infinity Ward has unveiled a new matchmaking system that will fundamentally change how PC gaming works for MW2.
Modern Warfare 2 may have been delayed by up to two weeks on the PC.