Users of the new site-targeting tool will be able to buy ads based on the number of times they are shown, a commonly used form of pricing, in addition to Google's traditional plan that charges advertisers only when Internet users click on ads.Currently the new program is available for a small number of advertisers but this will change over the coming weeks. Google's new site-targeting tool will also allow advertisers to choose on which site of the content network they want to advertise.
More info at Reuters