Just a quick note to say that this script on github from @clark800 has saved my bacon on many occasions. Usually for professional purposes, but on more than one occasion to restore my minecraft world to before I died.
Dropbox stores your previous versions of changed files, and allows you to restore any of these, however only one file at a time. This script will go through a specified folder and restore the previous versions (and deleted files) at the given point in time. Great for when you accidentally delete the wrong folder (or get blown up by a creeper you didn’t notice 😉 )