Back in August, Valve modified the Steam Subscriber Agreement, which provided a deterrence from suing Valve over frivolous issues. It also did not properly address the fact that a EU court ruling in July allows for the resale of digital goods. This is the issue that the German consumer group has a beef with.
The group also claims that Valve illegally coerced users into consenting to the new EULA. How? Apparently, it's because Valve would not grant access to their Steam library of paid titles until they agreed to the new terms.
This is not the first game developer that the group has set their sights on. In July, they went after Blizzard, claiming that they did not do enough to inform German consumers that Diablo III would require a persistent online connection to play the game.
How this matter is resolved may set a new precedent for many publishers and future legal battles. This includes EA who set up a similar EULA for Origin prior to Valve implementing their updated EULA for Steam.
(via Cinema Blend)