Dropbox is a personal cloud storage service (sometimes referred to as an online backup service) that is frequently used for file sharing and collaboration. The Dropbox application is available for Windows, Macintosh and Linux desktop operating systems. There are also apps for iPhone, iPad, Android, and BlackBerry devices.
To share a file, the user can generate a URL for it from the Dropbox website and send it out so that others can view it. Folders can be shared by sending an invitation from the Dropbox website. Recipients that don’t have Dropbox accounts will have to sign up to access the folder. Once a folder is shared, it will appear in the folder system for everyone who has access to it and all members will be able to make changes to files. All versions of files are saved.
Read more: http://searchmobilecomputing.techtarget.com/definition/Dropbox