See that really isn't the main use case for dropbox, dropbox is more like seemless backup and sync. You have a dropbox folder on your computer you work on stuff in, everything gets uploaded and revisioned while you are saving files and when you change computers everything is there.

You also get pretty good folder sharing with others and a web interface.

Personally though I've stopped paying for dropbox and might consider going back if they implement client side encryption for some users, but til then its waiting for a fast enough good enough replacement or for dropbox to implement it.