Infinity Ward and Activision have chosen to use Valve's Steamworks suite of tools for Call of Duty: Modern Warfare.
Significantly, they decided against Microsoft's typically more popular Games for Windows - Live.
Steamworks handles a smorgasbord of functions: game authentication, auto-patches, updates, achievements, anti-cheating and persistent player saves via the Steam Cloud.
The news arrives hot on the heels of controversy, after Infinity Ward announced there would be no dedicated multiplayer servers for the PC version of Modern Warfare 2.
Valve's Steamworks offers a matchmaking and lobby infrastructure, but Infinity Ward and Activision made no mention of these functions - suggesting that the bespoke IWNET platform will cover those areas itself.
"Steam is the hands-down leader in offering a community focused experience on PC and the inclusion of Steamworks has allowed us to deliver the most feature-rich PC version to ever come from Infinity Ward, which at the end of the day will mean the most to our fans," said Infinity Ward's community manager Robert Bowling.
Call of Duty: Modern Warfare 2 will be released on 10th November for PC, PS3 and Xbox 360. A Wii adaptation of Modern Warfare 1, and DS game Modern Warfare Mobilised, will be released on the same day.