http://www.videogamer.com/news/15-10-2008-9662.html
"A Ubisoft forum manager has posted new information regarding the copy protection in place on upcoming open-world FPS Far Cry 2 on PC.
According to the post PC gamers who buy the retail game will be able to install on three machines, with five activations for each system. Uninstalling the game will refund an activation. This process, known as a "revoke", will make it possible to install the game an unlimited number of times across three systems.
Upgrading your computer will not affect the activation so long as the revoke system is used when wiping your system for a fresh OS install.
Ubisoft has also confirmed that an internet connection will be required to validate an install or rovoke: "You need to be online only for a fresh install. An internet connection is also required to revoke the license when uninstalling the game. A high speed connection is not required," stated a forum post.
In a later post it was also confirmed that revoking all installs on a specific PC will free up an install for a new PC.
"Every time you revoke the activation you can install the game on a different machine. So yes, you could uninstall/revoke on three then put it on three completely different machines," explained the forum post.
Ubisoft also notes that "additional activations can be provided".
It sounds perfectly reasonable to us and you're only likely to find a problem if you must run the game across more than three systems.
Far Cry 2 is scheduled for release on PC, Xbox 360 and PC on October 24."
FarCry 2 to Use "Revoke" System for Unlimited Installs 
