MIT's Technology Review makes an important point regarding software vs. music/movie copyright infringement (Can Peer-to-Peer Stop Software Piracy?). If you're downloading warez, you never know what you're installing on your system. Could be the game you want, could be a trojan. There are no guarantees. This means that software is better positioned to fight internet infringement.

On its face, offering to sell a piece of software in a forum where users can obtain the same product for free sounds like a futile endeavor. However, the illicit nature and reputation of these networks makes these sales more likely. Here’s why: With the possibility for viruses so high when downloading a piece of software from these networks, consumers may be more likely to purchase software from a trusted source. “If you’re an intellectual property owner, you have to make it as easy to legitimately acquire your product as it is to swipe it,” says Garland. “People don’t care if an MP3 file is Sony sanctioned. But if you’re going to do your [finances] with a piece of software, you want to get the real McCoy.”

via JD Lasica