Remember the earlier speculation about a bot called MSRBOT and whether it was Microsoft related?
As it turns out, MSRBOT does belong to Microsoft Research in San Jose. The researchers at Microsoft finally put an identifying url in the user agent string.
Http Code: 200 Date: Oct 05 05:22:51 Http Version: HTTP/1.1 Size in Bytes: 7743
Agent: MSRBOT (http://research.microsoft.com/research/sv/msrbot/)