https://play.podtrac.com/npr-510313/edge1.pod.npr.org/anon.npr-mp3/npr/hibt/2016/10/20161014_hibt_airbnb.mp3A chance encounter with a stranger gave Joe Gebbia an idea to help pay his rent. That idea turned into Airbnb — a company that now has more rooms than the biggest hotel chain in the world.