HotelTonight is a mobile-only hotel booking app that has seen significant growth with over 6 million downloads and bookings in 100 cities across 12 countries. The document discusses what makes a great mobile company, including having a simple and focused user experience that allows for efficient task completion. It also provides examples of how HotelTonight has improved its product through design iterations and data-driven solutions to problems regarding multi-night bookings and checking out.