I emailed YPN support yesterday and asked if I could use Intellitext or Kontera with YPN ads on the same pages. (Intellitext and Kontera ads are similar, they are contextual and usually appear as double-underlined links on a page)
Support replied they are NOT allowed on the same pages as YPN, in no uncertain terms. I can only use them in "other" pages that do not carry YPN.
Another strike against YPN! (Google Adsense allows Intellitext and Kontera)
I agree. For me YPN has never earned as well as Adsense (strike one). As of a month or so ago I experimented with Kontera and then finally settled on placing IntelliTXT on my Adsense pages. Doing so turned out to be a significant additional source of income for my site (strike two for YPN).
I've just finished a revision of my site. Every time I came across a page that was showing YPN I struggled with why I should continue with them. The net result was I reduced my YPN exposure even further. I think its good to keep the YPN account open and live but I just give them a trickle of traffic now. Who could afford otherwise?