In the web hosting and colocation markets, Linux and to a lesser extent, FreeBSD have already won.
In other markets, like backend servers, database servers etc. Linux is gaining ground. On the desktop there is still the feeling that Linux is not quite there yet, though some have switched and done well.
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In the web hosting and colocation markets, Linux and to a lesser extent, FreeBSD have already won"
Windows keeps gaining market share in the web hosting market:
"Microsoft-IIS gain 935K sites, continuing an advance that has seen Microsoft steadily chip away at what once seemed an insurmountable lead for Apache. In our Feb. 2006 survey, Apache held 68% market share, giving it lead of 47.5% over Windows (20.5% share). In this month's survey, Microsoft's share has improved to 31.0%, narrowing Apache's advantage to 27.7%."
http://news.netcraft.com/