Uh-oh. A lot of gamers are going to be unhappy about this. It seems Grand Theft Auto IV for the PC will be outfitted with DRM, specifically SecuROM, which recently made news just a bit ago when it was discovered it was included in the Spore title.
While companies have a right to protect their property from piracy, oftentimes these DRM measures cut into a buyer's activities, restricting what they can and can't do with a piece of software they bought.
This version of SecuROM won't be quite as harsh as those initially included with Spore, which limited your installations to three times. Instead, in Grand Theft Auto IV, you will need to register your copy when installing it and the disc itself will need to be in the drive in order for you to play it. You can install it any number of times you'd like besides that. And though DRM is annoying, this is at least not as annoying.