One site I am working on at the moment is making near enough £3k a month from Adsense. Is it worth for us to change to YPN? We are based in the UK, I have read that the YPN should be available to UK users in 2006, but I can't seem to find a sign-up anywhere. Is Yahoo! generous? As sad as it sounds, I kinda like the free gifts that Google give at Christmas.
I just wrote a blog posting about my experiences after two years of YPN: http://www.admoolah.com/blog/index.php/2007/07/a-look-back-at-ypn-after-2-years/ Summary: It was good for a little bit in Spring 2006, now AdSense does better. Targeting sucks.
My suggestion is to not get excited about YPN. I've used it experimentally since the beta program was started (it's STILL in beta!!!!) and the program has progressed from bad to worse in that time. In summary, I would not advise anyone to use YPN if they have other choices.
Don't bother until YPN learns how to deliver a targeted ad more than 2x in a row.. by the looks of things, it might be another several years before they can figure it out.