The document discusses smartphone technology and mobile guest services provided by hotels. A smartphone allows users to access the internet, take photos, listen to music, and book travel arrangements or pay for purchases. The mobile guest service is a hotel tool that allows guests to order drinks or services from their phone via an app rather than visiting the reception desk, providing a more seamless experience. Examples are given of Marriott and Hilton's mobile apps that enable guests to check-in, select rooms, unlock doors with a digital key, and request amenities from their phone.