Relic revealed via its blog that the party is over for Games for Windows and its upcoming Warhammer 40,000 titles. The general consensus among PC gamers is that GFW support in earlier Warhammer 40K games was more of a hindrance than a help when it came to playing multiplayer.
Nevertheless, the horror seems to be abating: the upcoming Dawn of War II: Retribution will only use Valve's Steamworks. THQ and developer Relic seem to prefer Steamworks because it provides Steam community features such as groups, achievements, and Steam chat. THQ said that, in addition to Steamworks support, it is working on new matchmaking and ranking built specifically for Retribution.
The bad news is that Relic has changed the game from a regular expansion to standalone, which means that Dawn of War II owners are stuck with Games for Windows. Here is more on the decision to make the game a standalone expansion: