It's not just the Pricelines and Expedias of the world, it's also the hotels themselves which walk this fine line between "Yes, we want to be available on platforms like TripAdvisor, Expedia, Priceline, etc. We would also really like it if people just came straight to our website and booked that way."

So the competition is on a lot of different fronts, and a lot of very well-funded fronts, from Booking Holdings and everybody else, and is lesser on the experiences and restaurants.

Related: TripAdvisor sees hotel weakness lasting into 2019