Your post is a little confusing - do you mean - How relevant most a page with adsense adverts have to be to your chosen keyword to have your advert displayed there?
Who knows, only google would know. Test the content network out an monitor your referral logs and track conversions, so that you can monitor which sites send you the most sales. Then use placement targeting to only advertise on the best converting sites.
T_Media: adwords not adsense. They are so cryptic regarding how much content, i obviously know it must be relevant to the subject matter. My impression is they have always wanted straight forward factual info as opposed to just fluff to add additional text, any ideas? Thanks
I have seen a Googler use a page with about 50 words for a product listing as an example of a good quality landing page. I asked was it enough and was told yes. All content was relevant of course, and the page had the usual, privacy, about, etc etc.