At SXSW 2009, Foursquare introduced the world to the check-in. Five years later, it has 5 billion check-ins and counting, giving it one of the world's most powerful databases about where and what to eat or do in any given neighborhood. But users were confused. Was Foursquare meant to replace Yelp or help them find their friends? To survive, the company realized it would have to radically reinvent itself. Founder and CEO Dennis Crowley came to a striking conclusion. If the company wanted to survive, it needed to make its riskiest decision yet: killing off the check-in and splitting its app in two.