John Legere is the outspoken CEO of T-Mobile USA. Previously serving as an executive for AT&T and Dell, Legere can now be seen promoting T-Mobile in any way he can, especially through his avid use of Twitter. Legere was appointed as CEO of T-Mobile in September of 2012 and also sits on the board of the CTIA. 

T-Mobiles "uncarrier" approach ditches contracts in favor of simple plans for customers, including unlimited international roaming as well as early device upgrades.