Which is the most powerful form of advertising in the Hospitality business?

In the hospitality business I think the most important one is the word of mouth because in this domain the customer can give a good/bad feedback immediately according to the service and to the quality of food or other product.

Hospitality business means star rated Hotels, Airlines, Tour Reservation company, Restaurant, Clubs, Bars, Resorts, Cruise ships, amusement parks etc

For all of these businesses , a dedicated very user-friendly website with all necessary information i.e location, schedule, net pricing, various options for services and facilities of internet reservation/ booking  is the most important. The website shall act a one stop business shop so that people can buy air-ticket, book hotel/ resorts, car in one sitting. Example: Website of Emirates Airlines, Booking com and flight  engine  like Kayak.com or travelocity etc.