Nook: Barnes & Noble's Kindle rival — split off in 2014, shut down in 2016

Barnes & Noble launched the Nook e-reader on November 30, 2009 at $259 — the bookstore chain's answer to Amazon's Kindle, and the centerpiece of its digital strategy. The company poured resources into hardware lines, content stores and a $300 million partnership with Microsoft in 2012.

The strategy bled: Nook sales declined as tablets and phones absorbed the market, the Nook HD/HD+ hardware line was discontinued in fiscal 2013 due to financial losses, and in 2014 Barnes & Noble announced it would split the company in two — separating the Nook division from the bookstore business. Microsoft ended the partnership in December 2014.

The end came in steps: Barnes & Noble stopped selling digital content in the UK, and on March 15, 2016 it shut down the Nook App Store, Nook Video and the UK Nook Store, pushing users toward Google Play. The bookstore survived by cutting the Nook loose — the e-reader war had been won by ecosystems, not devices.