From Jensense, The Authority on all things Adsense:
Publishers have often complained about the rigidness of the AdSense policy that prevents publishers from running AdSense on the same page as another contextual ad program. So running AdSense & Yahoo Publisher Network on the same page during the same page view would be a no-no, but rotated 50/50 would be perfectly within the AdSense (& YPN) policies and terms. But not any more. Their competitive ad policy has gotten much, much tighter when they updated their AdSense policies today.
Originally posted on January 18, 2007 @ 4:44 am