Originally posted here by MsMittens
The Akami ones are someone else's. (web tracking?). outlook.microsoft.com seems to present a microsoft website although it's hosted elsewhere (??). The hotmail ones do resolve to hotmail or msn. The nexus2.dev.hotmail.com is definately going to hotmail (via traceroute).

Basically, MS still probably has a few *nix boxes around. I wouldn't be surprised. If they are going to provide interoperatibility, wouldn't they need some live stuff to work with?
Akami is MS's ISP