I’ve been using Dropbox for over a year now. It just works. It copies stuff you save to a specific folder on your computer to the cloud, while also keeping old versions around. I’ve set up my daughter’s computer to save documents to the Dropbox folder by default. Now it is so much easier to find what she has worked on and to go back to a previous version if she accidentally erases her document.
Her important documents are backed up and available if her computer dies. I share the folder she works in, and can edit or comment on what she’s done and save those changes on my machine. Dropbox synchronizes the changes automatically. It works seamlessly and quickly.
The best description I’ve seen of Dropbox comes from Bill Gurley who said “once you begin using Dropbox, you become more and more indifferent to the hardware you are using, as well as the operating system on that device.” I’ve personally enjoyed the service for quite a while, and the more I learn the more I respect what they are trying to do.