It is not clear, at this time, if the issues with C&C4 have anything to do with denial or service attacks or pirated versions of the game, but the game's community manager is asking for more information from players experiencing problems in this forum post.

DRM that requires a constant Internet connection is becoming a bigger issue as of late, especially when it is required to play singleplayer content. The logic follows that gamers would want to play offline games when they are without connectivity.

Blizzard's upcoming StarCraft II will require Internet access to validate new copies, but will then offer an offline mode that will allow for campaign and skirmish play.