Dropbox offers a simple solution to backup some files outside of your computer. It even offers the possibility to synchronize between different computers and the Dropbox server. The tool is available for Windows, Mac and Linux. Your documents are saved encrypted. Documents in the public folder can also be made available to others by sending them the public URL. Additionally you can share documents within your account with other dropbox users. Dropbox offers you 2GB of free space. Additionally there are different payed packages to increase your space. When you register via my Dropbox link you get an additional 250 MB for your account (and so do I).