Foursquare likes to show off its data-crunching prowess with predictions. It forecast the sales figures for the iPhone 6s and 6s Plus, for instance, and the decline in revenue, almost to the burrito bowl, for Chipotle following the E. coli mess. The company currently derives ninety per cent of its revenue from allowing a variety of businesses to use not just its A.P.I. but its data, too.