Everyone thought Mark Zuckerberg was crazy to buy a 13-person app for $1 billion — now Instagram looks like one of the most brilliant tech acquisitions ever made

In April 2012, Facebook CEO Mark Zuckerberg did the unthinkable. With the company about to begin its IPO roadshow, Zuckerberg made a surprise acquisition of a two-year-old photo-sharing app called Instagram. What’s more, Zuckerberg paid out the nose for it, shelling out $1 billion for an app that …