Activision Blizzard (as well as Sony and a handful of other publishers) are being sued by Uniloc - a company specializing in computer security and copy protection initiatives. It appears that the abovementioned publishers, supposedly, infringed on Uniloc's patents for what's basically DRM.

Uiloc claims that the defendants "directly and/or indirectly infringed at least one claim of the '216 patent" by "among other things, making, using, offering for sale, selling and/or importing a system, device and/or method for reducing software piracy, reducing casual copying and/or reducing the unauthorized use of software, including without limitation." As a result this has "caused reparable and irreparable damage to Uniloc and Uniloc will continue to suffer damage for which remedies at law are inadequate unless each defendant is enjoined."

Thanks, GamePolitics.