According to documents obtained by TechCrunch, Microsoft is prepared to pay $1 billion for Barnes & Noble’s Nook ecosystem. The Nook tablets could be on their way out in favor of apps and software that run on third party devices. CNN reports Barnes and Noble has had difficulty keeping up with more established digital operations. “The bookseller has been unable to keep up with Amazon’s successful Kindle e-reader…Nook sales have disappointed for several quarters, despite major device upgrades like the Nook HD release this past September.”