Nook this holiday season? Here's hoping you got in the door early, because bookseller Barnes & Noble claims that the Kindle-competitor has sold out for anyone hoping to gift the thing this year. According to the New York Times, B&N says pre-orders on the device have exceeded its expectations, and the well has now run dry on forthcoming stock. To make up for the loss, the seller is offering placeholder certificates for buyers, with a promise that the next round of devices will be shipping out around January 4th. Are suburban moms to blame? Only B&N knows for sure.