Valve has announced MW3 is returning to Steam

 

Valve today confirmed that the year’s most anticipated game, Call of Duty: Modern Warfare 3 (PC), will use the Steamworks suite of services. Pre-purchase reservations are now available via Steam, a leading platform for PC and Mac games with over 30 million accounts around the world.

 

The PC version of the product will be powered with Steamworks for both the digital and tangible versions of the game and, as with all Steamworks titles, offline play will also be supported along with Auto-Updating, Achievements, and more. Call of Duty: Modern Warfare 3 will also support dedicated servers on day 1.
 

–SOURCE: Valve Press Release