It serves approx 32 bytes but it serves it to such an enormous number of machines that I have been curious as to how it is set up.

Netcraft says: F5 Big-IP Microsoft-IIS/7.0 213.199.181.90

But I am curious as to what the real details of the setup are.

probably a small cluster of w2k8 servers? I doubt ms would be using anything else.

Are you sure about that?

You mean like how Hotmail ran Apache? It's true that not all MS properties run IIS, but there is no indication they'd lie about it.