The MBS group has gone through a series of VPs over the last while. MBS was initially headed by Doug Burgum.
Burgum announced in September 2005 that he would step down the following November as the head of the MBS group, which had been steadily losing money.
In the summer of 2006 the MBS group was transitioned to the larger Microsoft Business Division that encompasses Microsoft Office, SharePoint Server and Microsoft unified communications products. The move was made to help align Microsoft's business applications group with the rest of the company.
Finally, in September 2006, Satya Nadella was named to the top spot in the MBS division—a job he held for all of six months until he was transferred over to head the newly created Search and Ad Platform group.
Microsoft then named Tami Reller, corporate vice president of MBS at the time, as the interim leader of the business applications division. The plan was that Reller would work with Jeff Raikes, president of the Microsoft Business Division, to find a new leader for the MBS group.
It is rumored, however, that Reller was bucking to maintain the top spot in the MBS group, and that she has been passed over in favor of Tatarinov.
Kirill is a dyed-in-the-wool systems management guy that came from BMC so this is a bit of a surprise. I'm not sure if it means he's being rewarded or being handed a boat anchor - I guess time will tell.
In the meantime, I'm hoping the change at the top of the WEMD group will lead to some windows being opened and some fresh air to be let in and some hot air to be let out...