DRM is Digital Rights Management.
It is additional software/steps you must go threw to play a game. This helps prevent piracy, most of the complaints are the versions where you need to go online and log into the game company website to play the game, this includes single player mode. An interruption of the internet connection will terminate continued game play.
DRM is a failed technology and it comes down to you wanting to support the game developers so they can make more. Swen is cool and awesome, but he still needs to eat and take a vacation to Hawaii (maybe island of Maui?) you know.
