Since Tim Flight wrote that rotating YPN & AdSense was a bad idea, I have had plenty of emails and instant messages on the subject.
This is a problem I have not had whatsoever, and I have been rotating AdSense & YPN on JenSense for quite a while now. I have it set to rotate per page view per person (so while you will hit reload and see the the same ad program, the next person to hit the page would see the other ad program). And stats show page views are pretty evenly split between the two.
But when Tim phoned support and chatted with an engineer, this is what he found:
So the next logical question was why am I getting PSAs on YPN? After having a few of the YPN engineers look at my site they figured out the reason it was getting PSAs was because I was rotating pageviews between YPN ads and AdSense ads. Basically the YPN bot that crawls pages to determine the content was getting confused because the page content was constantly changing and the YPN ads were there one second and gone the next. So each time a YPN ad was displayed it triggered a new