The nook does not use battery power to keep an image on the screen. E-ink is not like an LCD display that has to keep an electric current running to keep the image up. E-ink uses battery power to change the image, and then that image is static until current is applied again to change it. So when you got yours in the mail, it wasn't "on," it was in a special factory off mode, displaying a welcome screen.
This is explained in the nook's instructions.
Also, there's frequently a ghost image when the display changes, unless the e-ink flashes the whole screen white/black and then to the next image. This happens to all e-ink displays, and is why they all flash when you turn the page in a book.
Last edited by rinkrat19; 02-19-2010 at 04:53 PM.