I just read Tim Flights post: Rotating YPN and AdSense is a Bad Idea
It basically says that rotating between AdSense and YPN with every page view is a bad idea because it confuses the YPN bot and cause Run of Network (RON) ads.
“PSA”s (It seems that’s what YPN calls the ads like vonage.com and flowers.com for some reason).
I’m not sure if I agree with this. When I rotate ads I usually get 2 or 3 on target ads and 2 or 3 off-target ads. So it seems like YPN knows what the page is about, they just show relevant ads in only half the ads, as if they don’t have enough inventory to fill all four or five ad positions in the ad unit.
I would be interested to hear more experience with this and to see if YPN has anything to say about it (they really need a blog). I might try experimenting with this a little myself.
(Found via ProBlogger)
Update: YahooSarah has cleared up the PSA terminology confusion on a Digital Point Forum post. They are actually RON (Run of Network) ads.