OTAs (Online Travel Agents) for example booking.com, hotels.com, laterooms.com etc combine prices and inventory from hotels onto the one website. The result is a great experience for the user as all hotels in a city can be browsed easily and quickly on the one website. Without OTAs, users would have to check every individual hotel's website. Once someone finds a hotel they wish to book, theycomplete it with the OTA ie the user transacts directly with the OTA, not the hotel. The OTA sends on the reservation fee to the hotel in question, minus the OTAs commission. While hotels detest the high commissions charged by OTAs, inevitably they will regularly rely on them for volume. Obviously hotels endeavouras much as they can to limit their dependence on the pricey OTAs.
At first glance, Meta Search Engines look similar to OTAs in that they give users a complete list of hotel inventory in a specific location. However, unlike OTAs, meta search engines don't sell hotel rooms. In fact, they actually charge hotels and OTAs on a cost per click basis to have their inventory on their sites.
OTAs purchase this traffic, secure the booking and then charge a commission to the hotel that actually equates to many multiples of what it originally paid out for the traffic. Sophisticated hotel marketers don't let this happen. Instead, they send their inventory directly to the meta search engines, purchase the less expensive traffic themselves on a CPC basis which in turn reduces their costs per acquisition.