True, I think logic suggests most people find it convenient to just click the result link on Kayak, which has made it so easy compared to Oribts, which has its own booking engine. So I am guessing they just make a very small percentage of the sale just for referring.

If as you say the hotel search is the real deal, it makes sense. Which leads me to the next thought, wonder why hotels haven't caught up with the airline industry in having a fairly realistic price listing on their own site? In fact, most of the times I am ok just booking using priceline bidding for hotels.