Sure, Windows is expected to run on 1 billion devices by 2010. But a loud minority is making its voice heard by moving to Ubuntu Linux. In fact, Canonical’s marketing materials state that Ubuntu now has more than 8 million users.

Alas, measuring Ubuntu’s active installed base can be tricky since a single copy o the operating system can be freely installed over and over again on multiple systems. And in mid-2007 during the Ubuntu Live conference, Ubuntu/Canonical founder Mark Shuttleworth estimated the operating system’s installed base at 6 million to 12 million users.

But apparently, Canonical has narrowed down that figure.