A P2P protection program that prevents malevolent servers from accessing your computer while you illegally download movies, TV shows, music, books, and other types of "intellectual property." The program doesn't hide your IP address, but it does prevent companies like the recording industry from collecting evidence about what you're downloading. Peer Guardian only blocks IP addresses in its block lists, so it's not 100% effective. Despite this, it's better than nothing.
Peer Guardian 2 is often referred to as "the Condom of the Internet."