Ken Chenault, the outgoing CEO of American Express, is quickly building a platform in the startup world. Chenault announced plans to leave his position as the head of Amex last October, ending a 17-year run, and this month he’s bagged a trio of top positions within the tech/startup world. Facebook appointed him to its board on January 18, last week Airbnb said he’s joining its… Read Morevia Tingle Tech