Here's one of those good ideas that makes you wonder why it took so long for someone to come up with it. Addonics has introduced its Network Attached Storage (NAS) adapter, which is a $55 device that lets you plug a USB-powered external drive in one end and then connect an Ethernet cable to the other end that runs to your router.
The compact adapter would seem to be a great idea if you already own external storage that you would like to share over a network, and could also be a cheap alternative to a dedicated NAS device (since the device and an external drive, depending on capacity, could cost around $100 less than a dedicated NAS drive). It also works as a print server if you swap your drive for a printer to plug into the USB port. The unit can even be set up as a FTP server for remote users, a BitTorrent client, or a UPnP AV server.
The NAS adapter's one obvious weakness would be that it only has a single USB port. To overcome this limitation, Addonics sells storage racks and towers that can house multiple drives that can connect to the adapter and provide RAID functionality. With that additional cost, however, this solution faces competition from network storage enclosures offered by other companies. Still, this could definitely appeal to those with a external hard drive or large flash drive who want a fairly cheap way to turn it into NAS devices.