The document discusses Dropbox, including what it is, how to set it up, how to add files, and how it protects users' files. Dropbox is a file hosting service that allows users to create a special Dropbox folder on their computer that automatically syncs and shares files with their Dropbox account online and across devices. The document provides step-by-step instructions for signing up and installing the Dropbox desktop application. It also outlines some key advantages like cross-device access and convenience, and disadvantages like security concerns.