Omnicom Media Group may be the largest company that you’ve never heard of.  With $13bn in annual revenue and over 60,000 employees worldwide, OMG is a behemoth in the world of advertising, media buying and marketing.  Few industries have been disrupted more than media and very few executives have thrived throughout the tumult of disruption.  Julian Porras is one of the few, a veteran of Latin American marketing and advertising whose wisdom was built on the battlefield of volatile Latin American markets.