Morning Joe 09/20/13

Fortune names its 2013 '40 Under 40' list

Fortune's Leigh Gallagher joins Morning Joe to reveal the magazine's 2013 "40 Under 40" list. Gallagher explains why the magazine chose Yahoo's Marissa Mayer as its top pick for the year. Twitter's Jack Dorsey comes in at number two. ... more Duration: {{video.duration.momentjs}}