It seems that Google has released a search engine that you can customize to the sites that interest you. You can then integrate this search engine into your site. Their seems to be revenue sharing in ads similiar to the current Adsense search addition.
Can this lead to a search brokering industry where you directly pay website owners for adding you to their own customized search. That would seem to be a more effective marketing technique than opting to buy ads through Adwords. That’s just my two cents though.