As a kid, Troy Carter dreamed of being a rapper, but soon discovered he was a better manager than a musician. He took Lady Gaga from obscurity to stardom – helping shape both her music and her brand. Then he turned his gift for spotting talent to spotting investment opportunities with his company Atom Factory. PLUS, for our postscript "How You Built That," we check back with Robyn Gerber for an update on Parkarr, a mobile app that helps drivers find street-parking.