Dropbox is a cloud storage service that allows users to create a special folder on their computer that syncs and appears the same across all devices. Any files placed in the Dropbox folder are automatically backed up online and accessible from any computer or mobile device through the Dropbox website or app. The document provides step-by-step instructions on how to install Dropbox, set up an account, add and organize files, create folders, upload files, and share folders with other users. Users are invited to comment on the author's blog with any additional questions.