Hilton, like other area hotels, now limits the inventory it makes available to third-party web sites. It gives them enough that customers who visit Expedia for price comparisons can see where Hilton falls. But it no longer gives those sites discounts; Hilton and almost every other major hotel group now guarantee that the best possible rates can be found only on their own company web sites.

"We've not eliminated these partnerships, but we've had to control what we were offering to try to drive consumers to our web site and buy through our web site," Baublitz said.

Chip Conley of Joie de Vivre Hospitality said that his company offers half as many rooms to third-party resellers as it did three years ago.

The Orbitzes and Hotels.coms of the world continue to be useful for price shopping, but more and more customers are going straight to the source to make reservations.

Chip Conley likens the third-party resellers of three years ago to Wal-Mart; they used to have tons of choice and unbeatable prices. Hotels have changed that.

Third-party sites "have to go out of being a Wal-Mart and low-price leader and become more of the Consumer Reports for hotels," Conley said. But that's something he'd like his own sites to do as well.