The Barnes & Noble Nook device has been selling by the millions, but the Nook 3G has been struggling. According to a source with Engadget, the Nook 3G will continue to sell until the stock is exhausted. And the book retail company has been encouraging retail partners not to send out any more bulk orders. The reason for the discontinuation is rumored to be because of a lack of supply not because of the lack of bulk sales.