As marketers slash their ad 2009 budgets and Madison Avenue continues to purge talent (3,000 at Omnicom alone), it turns out that even agencies at the top of their game are proving vulnerable. Back in June I chronicled the diefied admiration Crispin Porter + Bogusky's Alex Bogusky has lapped up from both his employees and the industry for building arguably the hottest ad agency in the country ("He looked like Jesus," confessed one blushing creative). To the surprise of many, yesterday Crispin--which had huge client wins this year including Microsoft, Old Navy, Hulu, and Guitar Hero--proved mortal, cutting 60 of its 900 employees, some 6% of its staff. A spokeswoman for Crispin told AdAge, which recently crowned the Boulder-Miami shop 2008 Agency of the Year: "On a comparative basis, CP+B's business is doing well, but we are not immune to the constriction of the economy." Hopefully it's just a case of course correction after overagressive expansion. Because if it's not, and a seemingly untouchable shop like Crispin cannot stay immune, the ad world is in serious trouble.