I work for the company that delivers ads to travelers before they travel, below your printed boarding pass. And ads that work well are ones that are contextually relavent to actions they are about to take or might take while on their travels. But the CPM is much higher than just random search terms, but it takes that guess work out of what internet ad servers are trying to do. We know exactly what the person is doing and can deliver ads to them based on where they are going, coming from and such. Most people searching for mortgage rates are not interested in the history of mortgage rates they are interested in the current rate and how they can perform the next action of refinancing, which means a big payout to the lender.