While I don’t know the why’s or what’s it is reported by netcraft.com that the ip addresses used to resolve http://www.bing.com is running on Linux OS. Screenshot, Live Page

Now, in Microsoft’s defense I cannot find another source to be sure as they use p3p in their html headers.
So the Linux OS could be netcraft reporting a load ballancer or who knows what… still you think if Microsoft was using one of it’s own technologies it would proudly be displayed on the home page.

Discuss below:
David Bates

@Rexm pointed out that StackOverflow had this question posted as well. Link

Another Note: It has been said to me many times that this probably Bing’s CDN and not Bing’s actual webserver. I wrote this post because if you type Bing.com into netcraft it says Linux is the server type. I do agree with many and even said that it is more than likely to be load balancers than bing itself… It turns out that it could be Akamai that has the linux servers than Bing being hosted on Linux servers… It should also be noted that Akamai is the worlds largest CDN, but I still find it interesting that Microsoft would have anything Linux related in their server platform even if it is the CDN.