Windows 7 arrived just two weeks ago and so far it's selling quite sell. With Mac OS X 10.6 Snow Leopard arrived less than three months ago, and Ubuntu 9.10 arriving last week. It seems to be a good time to start watching market share for operating systems. At this point in time, Windows continues to dominate with more than 90% of market share, Mac OS is above 5% mark, and Linux is just under 1%. In October, Windows was the only operating system not to show positive growth.