See that image of a USB stick below? It is very similar to the flash drives that are out in the wild. Except that this also comes with a software that is programmed to automatically take back-up copies of files from the computer without any human intervention.
This new Lexar Echo SE Backup flash drive comes with a storage capacity of 128GB. While that is definitetely not enough to backup everything on your 500GB computer, it is definitely a great deal for a netbook or one of those computers with a smaller storage capacity.
Before you get excited, there is one big roadblock though. The price. The Lexar Echo SE flash drive is priced at a whopping $350. At that price, you could buy another netbook and play with both of them. Not sure, if anyone would want to buy at that price. But still, looks interesting.