The current contextual algo is not giving enough weight to the title tags, h1 (et al) tags and other such indicators of what a page is truely about, this allows for a single string to dominate the evaluation of context. In my limited testing of YPN ads (not on properties I own) the ads were too easily dominated by a single term. The whole page could be about poetry (or some other low-end niche) and a single mention of a larger niche (not necessarily a higher paying one) would dominate the ad serving.
This will need to be addressed before it goes live or the CTR won't be as good as AdSense.
