Online travel agencies (OTAs) offer users the possibility to book their holidays online. Well-known platforms such as Booking, HRS, or Expedia provide additional information like hotel reviews, travel tips, or package holidays. Often OTAs also act as tour operators. Hotels and tourism-related businesses can register to reach potential guests. In order to do so, information such as room availability and prices must be provided. If a stay is booked through the online travel agency, usually the hotel or tourism-related business has to pay a commission fee. Nowadays the majority of reservations are made via online travel agencies, transforming them into an important distribution channel for tourism businesses.