When Foursquare debuted at SXSW in 2009, the app was all about taking out your phone and clicking a button to check in to your favorite bars and restaurants. But the service has matured significantly since its first visit to the popular Texas tech conference, which cofounder and CEO Dennis Crowley returned to this year for the umpteenth time. In this video, Crowley discusses how Foursquare has grown to 35 million users who have shared 4 billion check-ins, which are helping to power the startup’s increasingly popular search engine. Its location data are also powering a number of third-party services, from Path to Instagram to Uber. And the company is now toying with the idea of a sort of passive check-in, so you no longer have to fiddle with your phone to tell it where you are–there are enough signals out there for it to do the work itself.