In my estimation the USB port is only for connecting a powered hub to.
From the powered hub, you should be able to connect a keyboard and mouse, and pendrive or harddrive, though I don't know if:
1- The device can recognize a USB hub
2- The device can recognize a keyboard
3- The device will have a cursor in the future for mouse.
As far as I see it, the e-ink screen works pretty fluently drawing things, but starts flashing considerably when erasing things (like probably all e-ink devices out there).
It is basically turning a dark pixel into a white one that seems to be the most difficult....