"The proportion of internet users running Windows has dropped below 90% for the first time. While the dip may be more pronounced thanks to a timing quirk, it’s symbolic of a consistent trend.

The figures come from Net Applications which monitors visitors to websites owned by its clients. That’s not a perfect measure but as the client list runs into the thousands, it’s a pretty decent sample size.
(According to Mac.Blorge)
During November ‘only’ 89.6% of users were running Windows, down from 90.44% in October, which is apparently the biggest monthly fall in the survey’s history. Mac OS X is up to 8.9%, with Linux at 0.83%.
The study noted a significant fall in XP’s share and rise for Vista which suggests the effect of the removal of XP from most mainstream sales has started to kick in.
It was bad news all-round for Microsoft as the browser figures showed Internet Explorer fell below 70% for the first time, with Firefox breaking through the 20% barrier."