For media companies, the Cannes advertising festival is all about getting face time with top media buyers and advertisers. Yahoo CEO Marissa Mayer missed a golden opportunity to do just that last week. Last Tuesday evening, Interpublic Group arranged a private dinner at the swanky L’Oasis for Ms. Mayer to meet executives from marketers such as Mondelez International MDLZ, brewer MillerCoors and Greek yogurt maker Chobani. It was supposed to be a chance for Interpublic and some of its clients to get a first hand update from Ms. Mayer on what Yahoo has to offer. But Ms. Mayer was nearly...
