It all began with a stop at a red light.

Kevin Salwen, a writer and entrepreneur in Atlanta, was driving his 14-year-old daughter, Hannah, back from a sleepover in 2006. While waiting at a traffic light, they saw a black Mercedes coupe on one side and a homeless man begging for food on the other.

“Dad, if that man had a less nice car, that man there could have a meal,” Hannah protested. The light changed and they drove on, but Hannah was too young to be reasonable. She pestered her parents about inequity, insisting that she wanted to do something.