In Thrive, Arianna Huffington wrote a passionate call to arms, looking to redefine what it means to be successful in today's world. In a commencement address she gave at Smith College in the spring of 2013, Arianna likened our drive for money and power to two legs of a three-legged stool. It may hold us up temporarily, but sooner or later we're going to topple over. We need a third leg - a Third Metric for defining success.