The introduction of Windows Vista signaled the beginning of the end for Windows XP. Ever since Vista has hit the shelves in January 2007, XP users have been converting at a slow but steady pace to the new Windows client available. Starting with 2007, XP's dominance over the operating system market began to erode irremediably to Vista's benefit.

According to the statistics delivered by Net Applications, XP dropped to a share of just 78.37% in November 2007, from 85.02% in January. At the same time, Vista is on an ascendant path that has seen the operating system increase its foothold on the market, by approximately 1% per month. From 0.18% in January, Vista has grown now to a share of no less than 9.19%.

And if Microsoft's latest operating system conserves its momentum, it will break the 10% market share milestone by the end of 2007, a percentage roughly equivalent with 100 million copies sold worldwide. One year after Vista was released to manufacturing, the Redmond company claimed to have shipped over 88 million Vista copies to its channel partners.

A distant runner-up on the OS market, Mac OS X is also experiencing consistent growth, but at a slower pace compared to Vista. Apple is, of course, benefiting from the recent launch of Mac OS X 10.5 Leopard, the successor of Mac OS X 10.4 Tiger. Overall, Apple's foothold on the operating system market has steadily increased this year, growing with almost 1% to 6.80%.

Linux remains the indisputable underdog in the three-horse race against Windows and Mac OS X. The latest data places the open source operating system at just 0.57% of the operating system market, a score that does little to position Linux as a viable alternative to Windows or OS X, or as a worthy opponent, for that matter.