Microsoft VP Joanne Bradford has left the company and will join Los Angeles-based ad agency Spot Runner. Even with a new title of EVP, it's hardly a leap up the ladder. Our guess on why Bradford bolted? A former executive at Microsoft and Yahoo told us, " I shudder to think about a MSNBC.com and Yahoo News integration." Bradford's departure plans likely came together not long after Microsoft CEO Steve Ballmer made it clear he favored Yahoo's brands over the MSN portal Bradford ran.