USB keyboards can be used to simplify entering search items(works sporatically on my 721). They are supposed to be using it for the new PocketDish portable player soon. SInce the USB port is controlled by software, it is pretty much only for what they allow. There was a guy that managed to use his 721 as a webserver at one point using a USB-> Ethernet adapter. However, the 721/921's system is on the hard drive, while it looks like the 522/625/942's is loaded into an NVRAM setup, so it may be harder to modify.....