The numbers don’t lie: football is America’s most popular sport. A lot of credit is due to former NFL commissioner Paul Tagliabue. Over the course of his tenure, Tagliabue was responsible for innovations both on the field and off: from huge growth in revenue to peace in player-owner relations. There’s a lot we can learn from him -- he says that the challenges he faced with the league are “a microcosm of the challenges that most businesses have.”