Splitting Nook from Barnes & Noble may not be a good idea for the digital branch after all. In releasing their fourth quarter earnings, Barnes & Noble showed an overall positive holiday quarter, but Nook is bringing them down. Nook revenue fell 55% over last year, casting doubt on which of Barnes & Noble’s two halves (physical or digital) is really failing. Nook’s earnings count digital devices, eBooks and accessories. That includes the Samsung Nook, which was meant to resurrect the brand with regard to hardware.