incrediBILL - 3:37 am on Jun 8, 2010 (gmt 0)
Google gave no warning.
That's because Google typically only warns you of directly infected sites.
Infected ad networks are a real beast to catch because the ad network rotates the ads so you may never see where it came from a second time.
If I didn't earn off advertising I'd say this problem is almost a good enough reason to run AdBlock and NoScript to everyone.