Valve has announced that not only will Call of Duty: Modern Warfare 3 be available on their Steam platform, but it will also be using the full suite of Steamworks services.
If you pre-order the game now, you'll be able to jump straight in when the game releases. Steamworks will allow for automatic updates as well as achievements.
Also announced was something that will come as a relief to PC gamers - Modern Warfare 3 will feature support for dedicated servers. This was glaringly missing from Modern Warfare 2.