Just to make this clear:

She is powering the N810 by getting the power FROM the USB port of, for instance a PC, but feeding that power INTO the normal regular power port of the N810, that is NOT INTO the N810's USB port. This is being done by using a custom cable she built.

You can check this by looking at the usb power cable she built by cutting some other cables, as explained in her site.

She is NOT feeding power into the N810 port to charge it ! Beware of this you could damage your Tablet if you do so...

Nokia sells a: "Nokia Charger via USB port CA-100" which works great for charging your N810 or your phone from your PC USB port.

Hope this info is useful.

Best regards.