Jeff Kirschner is the founder and CEO of Litterati, the crowdsourcing app that has helped people all over the world clean up more than 6 million pieces of litter to date. Litterati isn't just cleaning up the streets though: the data collected by the app is actually transforming the way some companies do business. Jeff has also transformed his own career, from ad exec and screenwriter to green entrepreneur. He's got a lot of heartfelt insights to offer on how to tackle big problems, how to use data, how to tell the story and bring people on board... and how to navigate the joys and sorrows of a purpose-driven career.