Valve/Steam has exclusive control of access to any Steamworks game (you cannot use it without creating a Steam account and agreeing to the Steam Subscriber Agreement) so this should be a no-brainer.[/i]
You can't use any game that has Securom without activating it online. The game is then activated to your hardware, instead of being activated to an account, but really just 2 sides of the same coin. You cannot reinstall a game after 3-5 times without first making a phone call and begging for a reactivation, if you did not first uninstall the game if the game happens to have a revoke with it.
Steamworks, Securom, Tages, Impulse Goo, ect are all DRM who do the DRM protection differently, and according to what you guys are saying are all monopolies.
