It would be an understatement to say that Yahoo's experienced a rough patch recently, and Microsoft, with Bing launched and a search deal on the way, seems to be doing better. But Yahoo may still have a few tricks up its sleeve, and the company pulled off one by getting a Microsoft sales exec to join its ranks. This morning, Kara Swisher described Seth Dallaire as one of Microsoft's top ad sales execs, and then wrote,