I have noticed this about a week ago and I thought this will be very interesting to see who (AdSense or Yahoo) found out the violation and remove the ad first. However, it seems like Yahoo and AdSense both wait for the other to stop showing the ads. Funny! Funny! Look like AdSense And Yahoo are reluctant to remove ads from Big Big Publisher! See it yourself First go to www.pingoat.com then fill the form with your blog name, url, xml select the categories to ping and click 'go pingoat' See? Yahoo Ad VS AdSense Ad! When will it last? Who will win?
When you submit your websites it seems that the header template still holds YPN and the submitting page hosts google ads and they then colide together on one page. Not a big deal, I am sure they will hear about it and change it or wait for either publisher to contact them about the problem eventually.