Jimmy Kimmel was the biggest star of SXSW 2014. The host of a 50 year-old TV variety show drove conversations at a tech festival. He capitalized on one key trend in today’s media and advertising: when it comes to content, the key metric of success is not viewers or attention anymore, but the number of people who talk about it. Kimmel got people talking. Conversation—facilitated by the rise of social media and the democratization of influence—now caps off any marketing effort. Forget about viewers and readers in media. Forget about foot traffic, impressions in advertising. Conversation is what should matter to advertisers. Forget about Return on Investment, focus on Return on Conversation. Take it from two brothers who know: Edouard Minc, who gets a nation talking every week as Publisher of Paris Match (The French Life magazine), and Thomas Minc, Head of Strategy at NY conversation agency Cake.