

Every two weeks, a business-school case-study of one boardroom decision that reshaped a North American industry. Sears missed e-commerce. Blockbuster declined to buy Netflix. Kodak vetoed the digital camera.












On the morning of Sunday, May 19, 2013, Yahoo's board approved the purchase of the blogging platform Tumblr for about $1.1 billion, substantially all of it in cash. The company announced the deal the…