KeyGen.us let those who wanted to unlock their hardware and software products (and who didn’t mind breaking some rules) do so for free. The site included a wide range of cracks, downloads, serial numbers and keygens that could be browsed both by software and by hardware, and instantly downloaded to your computer.
The site was free to use, and open to any person who wanted to give it a try. You didn’t even need to sign up for an account to get started, although getting one let you comment on the site’s forum, and ask for help if you couldn’t get any crack or serial number to work.
KeyGen.us was taken down in early 2010, for infringing the rights of numerous third parties including (but not limited to) software developers and manufacturers.