With the new "Open results within my own site" feature of Adsense for search, there's quite a few interesting things that seemed possible. I was a bit confused on exactly what is allowed on pages that show the results, so I contacted the Adsense team to clarify. Basically most of it is common sense, but it's good to have the official word: No normal Adsense Units: You are not allowed to place normal Adsense ad units on a page that displays Adsense for search results. The Adsense ads are already integrated into the results (at top and bottom of the result page). No third-party ads: You are not allowed to display any third-party ads on result pages. These include CPM banner ads even if they are not contextual. Referrals: No official policy exists about displaying Adsense referral buttons on result pages. No modification of code: As usual you are not allowed to modify the code provided. This includes modifying the width and height of the frame. Original blog post -Adsense for search do's and dont's
That's true. However I saw quite a few sites that implemented it in conjuction with normal Ad units as well. That seemed a bit strange to me, and that's why I asked the question. I guess some people thought it might make the ads more visible or something...