The Most Popular Online Booking Sites in Travel, 2014 Edition

Skift Take
2014 is turning out to be a consolidation year, with big getting bigger. But there is lots of interesting jostling beyond leaders, and that's where the action will be rest of the year. Airbnb's rise has been spectacular, and will continue to break through on the charts.
Last year we started a once-a-quarter feature on top trafficked sites in various sectors in travel, using monthly data from competitive intelligence metrics service SimilarWeb.
Previously, we have done data dives on top online booking sites from October 2013 data, and then Feb 2014 data.
This ranking below does not account for direct sites of travel brands (airlines/hotels) themselves, which we have done in separate lists previously. Also, our threshold is roughly 5 million visits per month to the online websites of these companies, and does not count any mobile app activity, hence sites like HotelsCombined, Hipmunk, Ostrovok and others don’t show up.
Some observations from data below:
We are not combining all companies under one rank (as in all Priceline Group, or Expedia Group), but we're combining all one-brand specific country sites (brand sites) together (hence all of TripAdvisor country sites are under one ranking).
Booking.com is still killing it, and growing fast as well, despite its gargantuan size.
Priceline Group, which includes Booking.com, Priceline.com, Agoda.com and Kayak sites, is the leader by a huge margin.
Expedia brand (all country domain sites together) is third largest, but Expedia Group, which includes Hotels.com, Trivago, Hotwire and Venere, is the second most popular online travel booking company. And since Travelocity is now just a white-label site for Expedia, those 10.6 million visitors could count towards its total, too.
TripAdvisor is surely the biggest media-plus-booking site globally, and the second most popular brand if you add up all country-specific sites.
Remarkably, Airbnb is now the fifth mos