NEW YORK--(BUSINESS WIRE)--Marissa Mayer, Chief Executive Officer of Yahoo, has joined the roster of top brand leaders, agency innovators, publishing superstars, and creative luminaries speaking at this year’s IAB MIXX Conference, produced by the Interactive Advertising Bureau (IAB). Mayer will sit down with renowned journalist, Jacob Weisberg, Chairman and Editor-in-Chief of The Slate Group, on Monday, September 28, at 2:30 p.m. Eastern, for an on-stage conversation that looks at Silicon Valle