Booking.com says it offers 202,842 hotels globally and a new report says the Priceline Group -- Booking.com, Agoda and Priceline.com -- collectively is adding properties at a quickening pace.
Meanwhile, Booking.com's market share in Europe is believed to be considerably less than 10% and officials say there is plenty of room to grow there -- let alone in developing countries in Asia-Pacific, Latin America and Africa.
So how many hotels are there in the world?
And, what is the ceiling for Priceline, Expedia and other online hotel distributors?
When will they be "done?"
The number likely is anyone's guess and much of it hinges around your definition of a "hotel."
STR Global estimates that there are 187,000 hotels, offering 17.5 million guest rooms, around the globe.
The company defines hotels as properties that are rented nightly, with seasonality taken into account, and having a specified number of rooms.
Due to the legacy of how STR came to be through acquisitions, its estimate includes properties with 20 rooms or more in the US only and 10 rooms and more throughout the rest of the world.
"We are confident in these numbers, but also release them with the caveat that it is an ever-changing landscape with the explosive growth going on in some parts of the world (China, India etc.)," says Jeff Higley, an STR spokesperson.
That definition, of course, leaves out perhaps hundreds of thousands of other "hotels," including properties with less than 20 rooms, motels, hostels, residence hotels, apartment hotels, B&Bs, inns, guest houses and chateaus.
And, then there are vacation rentals and timeshares -- plus the peer-to-peer market of condos, apartments, houseboats and couches.
Other less-than-scientific guesstimates put the number of hotels around the world at around 400,000, with an additional 100,000 or so if you include B&Bs and hostels etc.
In a similar vein, one of the global distribution systems informally uses 500,000 as a guide to the number of hotels in the world, although this number would exclude hostels, guest houses and motels.
So, clearly there is plenty of headroom for Priceline around the world, and its Booking.com and Agoda units may be increasing their lead over Expedia by adding properties at a faster pace so far in 2012 than they did toward the end of last year.
That's the conclusion drawn by the Susquehanna Financial Group, which uses a proprietary tracker to keep tabs how many hotels sister companies Booking.com, Agoda and Priceline.com are adding on a weekly basis.
"Tracking supply additions is important because this can act as a leading indicator to transactions (equivalent to additional selection in e-commerce terms), typically leading to improved conversion/customer experience on the platform and larger share of market over time," analyst Herman Leung wrote in a note to investors.
The Priceline Group's supply included 200,900 hotels through March 19, Susquehanna estimates, and during the first quarter it was adding about 1,541 properties (hotels, apartment hotels, motels, hostels, residence hotels, B&Bs and guest houses) per week.
And, that is considerably faster than the 1,229 properties the group added weekly during the fourth quarter of 2011, Susquehanna says.
Europe was leading the charge while growth in Asia was relatively flat and North America was lagging, according to the Susquehanna numbers.
Hotel additions in Europe, largely Booking.com turf, increased about 82% in the first quarter to more than 852 hotels per week while hotel additions in Asia, where Agoda sets up shop, increased by five properties per week to 385 compared with the fourth quarter, the Susquehanna tracker found.
Priceline's strongest markets in Europe are Italy, Germany, France and Spain, while China is its leader in Asia, followed by Thailand and India, Susquehanna says.
In North America, Priceline's hotel additions slowed by about 21% to 180 per week during the first quarter of 2012 compared with the fourth quarter of 2011, Susquehanna found.
So, how has Priceline accomplished such a hotel build-up around the world?
Does the answer revolve around technology, commissions, word of mouth and/or reach?
But, it is undeniable that Priceline has been increasing its global workforce at a torrid pace, more than doubling it since the first quarter of 2010, when Priceline employed around 2,266 people.
Through January 31, 2012, Priceline employed 5,000 people, including 4,000 outside the US.
And, lots of them are working on building the hotel business.