"MS is still running Apache for Hotmail."
Really????? Netcraft says otherwise:
http://uptime.netcraft.com/up/graph?site=hotmail.com
Hotmail switched eons ago. Originally when Microsoft bought them they ran Apache they switched soon after.
Not quite so soon. While BSD was humming along easily, they had a hard time getting their inferior OS (then NT) to handle what UNIX was capable of. The migration took a very long time.