Booking Holdings

25 Moments that Mattered in 2015: To make our selection of 25 moments, we thought back to the stories that drove reader engagement and sparked discussion among both travel experts and the general public. Some stories were quick blips that represented bigger things while others were narratives that built slowly through out the year. Each one, though, spoke to where we are right now when it comes to the big business of global travel.

TripAdvisor's decision to expand travelers' fees for vacation rentals will please Wall Street and could put pressure on Booking.com, which adamantly eschews such fees, to do likewise.

The websites that have the most comprehensive set of lodging choices, whether they are hotels, vacation rentals, apartments or igloos, will dominate. Expedia, through its HomeAway acquisition and intent to develop apartment rentals in cities, knows this and is getting ready for the future of travel in lodging.

Priceline Group CEO Darren Huston touts his company's organic growth versus Expedia Inc.'s strategy of mostly acquiring companies that need to be put back on track. Rest assured, however, that Priceline would plunk down a few billion dollars on the right acquisition target. It just wasn't HomeAway, and TripAdvisor and Airbnb are too expensive.

While the big chains have tech and marketing people to optimize websites and their cost-per click campaigns, booking sites in transformation such as Booking.com, Trivago and TripAdvisor are squarely directed at making themselves more essential to smaller, independent hotels. It is another sign of the changing role of metasearch sites and online travel agencies in the mobile era.

TripAdvisor wanted to keep the details secret. But the price for finally getting the Priceline Group/Booking.com into TripAdvisor Instant Booking was playing the online travel agency exclusivity card. Expedia is shut out for now and can join later. Will Book on Google play a similar game?

Understanding how Priceline.com turns lurkers into customers is key to gauging its success.

As this TripAdvisor-Priceline Group partnership takes off, observe it closely because it signals a new stage in earnest in travel bookings -- the real emergence of third-party sites such as TripAdvisor and perhaps Google at some juncture that were primarily media sites as real forces in travel transactions.

Expedia's purchase of HomeAway sets the stage for big moves in the online booking sector.

Booking.com is telegraphing the fact that it is open to participate in Book on Google now that it agreed to participate in Book on TripAdvisor.