Glad to see Ubuntu getting 1.12% of the gamer population on Steam using Ubuntu to game. In a few more month, Windows 8 might be in the number 2 or 1 spot when people also switch to 8, OS X, Ubuntu, and other PC operating systems.
The Vista users could be Linux and Mac users which bought a computer with Windows Vista to play Directx 11 games, and install Linux as a dual boot PC, but their main operating system is Linux which they mainly use except for gaming since there are fewer compatible games for Linux. Vista users also could be Mac users which got a friends license key to install Vista on Mac with Bootcamp or Virtual machines like VirtualBox.
If users rarely use Windows, upgrading to Windows 7, and 8 would be not that worth it for them since they mostly use Linux, or Mac. Some people also dislike upgrading to newer versions of Windows because they dislike paying money to Microsoft which is a company they dislike, and don't want to support by paying for a new version of Windows.
Vista is not that bad of an operating system if all your computer hardware is compatible with Vista, and you have atleast 2GB or more RAM, and a dual-core 1GHz CPU.
