Microsoft’s purchase of LinkedIn is one of the most expensive tech deals in history. It may not be one of the smartest Jun 18th 2016 | SAN FRANCISCO | From the print edition “IMAGINE a world where we’re no longer looking up to tech titans such as Apple, Google, Microsoft, Amazon and Facebook...because we are one of them.” So wrote Jeff Weiner, boss of LinkedIn, in an open letter on June 13th. Not much imagination is necessary. Microsoft had just announced it would pay $26.2 billion to buy the professional social network, making it the third-largest acquisition in the history of the tech industry. The deal was accompanied by substantial promises from Mr Weiner and Microsoft’s boss, Satya Nadella, that the deal would transform businesses’ and workers’ productivity worldwide. Those pledges seem fanciful. Microsoft is paying a high price for a firm that has suffered its fair share of setbacks. Although LinkedIn is the largest professional social network by far, wi