Ever wanted an online backup solution for your important documents, have you ever lost a USB Key, or have you ever needed to share some documents with someone else.

Dropbox can do all of this easily, just sign up to dropbox install the software on all of your PC's and keep your dropbox folder in sync between them all, you can then even create a folder and share it with other people.

You start with 2GB but the more people you refer, like this http://www.dropbox.com/referrals/NTIyNjkxOTU5 then the more space you get, gaining 250mb for each referal.