If you do work on two or more computers, or work on teams, Dropbox might be a helpful tool for you. Working on multiple computers allows us to be productive more often, but it adds a layer of coordination. Do you keep emailing myself files or carry a USB drive back and forth? And ensuring that you are working with the most current version can also cause confusion.
Dropbox, in beta phase, could provide a better way. Download the software onto the computers that you use and want to be connected and link them with your single Dropbox account. It fits right into the file directory systems for Windows or Mac machines. You just have to drag and drop the files and they are immediately synced between computers. Revisions or changes made to the file are immediately available in multiple computers. Your Dropbox folder also has a public folder which you can share with friends and co-workers. This could help facilitate group projects where many people on many computers are working with the same files.
There is no online storage of files with Dropbox, but it does revision history, so if you accidentally save a file and want to revert to an old version or deleted a file, Dropbox can recover any previous version. Check out the video below for a complete demonstration of its features.