As usual, the first I've heard of it is right here! Anyway, my problem with it is that there's no indication what each click will cost. In other words how does one determine what to bid on a specific "GuideSite"? Or on their Sprinks SE?
I gave it a quick go. Sprinks itself doesn't seem to get much traffic but about.com must. I didn't get any hits directly from sprinks but did get some from about. However it was pretty limited becuase sprinks results sit on the bottom of the page.