Windows Update Runs on LinuxAccording to the folks at Netcarft, Windows Update Runs on Linux.
To some degree, it begs the question 'what's that site running'. After all, what is the Microsoft site? It clearly includes these global caches so the answer probably is - it runs a lot of things. I supose this is more an issue about how Netcraft does it's survey - and how it determines that a site is 'running' on a platform.
Like most statistics,