Yesterday I ran a test of 5,000 impressions. Substituted YPN for Adsense on pages that have been running a very long time. Used the exact same colors and sizes. Literally replaced code so that was the only factor that changed on the pages. Adsense pages average click through is 5x higher! Yahoo doesn't not place relevant ads on the pages. The pages I tested are highly targeted to a very specific niche. They are optimized for that niche and Adsense ads deliver RAZOR TARGETED HIGHLY RELEVANT ADS. In fact 1 in 3 visitors will click an Adsense ad on these pages. So if you want to make money stick with Adsense. If you want to line the pockets of Yahoo while they continue to dick around with publishers then be my guest.
I agree for now because Adsense is mature for years. YPN is afterall a beta. Adsense targets the visitors based on their viewing behavior across all websites and their searching terms in Google.com. YPN may not or cannot do that due to patent issues.
I wouldn't say it is broken at all, I get a much higher rpc from YPN then I did with Adsense so the amount of money I get from each is about the same.
it takes couple of days to show the relevent ads .. so basically you need to test for more then 3 days , then you will see how it works
I actually enjoy having yahoo ads showing on my site. They pay more per click than google and reports each impression correctly, unlike google. Nothing broken on my end except the ad targeting section. :\