Planet Money did a great podcast on this recently [1]. It's pretty cool how it works. [1] http://www.npr.org/sections/money/2016/04/22/475339930/episode-697-h

Planet Money did a great podcast on this recently [1]. It's pretty cool how it works. [1] http://www.npr.org/sections/money/2016/04/22/475339930/episode-697-help-wanted http://www.npr.org/sections/money/2016/04/22/475339930/episo...