Most of the highest traffic sites on the web use linux/unix with the exception of MS owned sites and a scattering of other sites. Smaller sites tend to gravitate toward linux as a matter of course due to lower operating costs and wider availability of hosting.
Oh, there was no mention of this statement being just web servers.
I'd think that across the server market as a whole that Windows had won that one.
Every organization I come across seems to have a small percentage of Linux servers, but Windows dominates. I'd be pleasantly surprised if the facts had it the other way around.