An OTA, like TripAdvisor or Agoda, compiles available hotel rooms so users can compare prices and other features. You can book your trip directly through an OTA.\r A travel search engine, like KAYAK, displays results from several OTAs and the travel providers themselves to help users find the best price. If you opt for a price or deal offered by another OTA, you'll get redirected to that site. If you choose a deal offered by the hotel or airline itself, you'll book directly with that travel provider.