Watch live now: Twitter, Viacom and Sir Martin Sorrell on TV and social June 20, 2014 , Be the first to comment Twitter CEO Dick Costolo and Viacom president Philippe Dauman join WPP founder Sir Martin Sorrell at Cannes for an in-depth discussion on the symbiotic relationship between TV and social. News Don’t miss the livestream: More... In brief: Former No. 10 adviser joins Quatro, Blair Metcalfe to move to MSL, account wins for Wild Card and Cogent, Kreab recruits Watch: What made PRWeek's Best Campaigns of 2015 work? Watch: A Requiem for Meters marks passing of analogue utility meters Top and Flop: November 2015's biggest PR fail and greatest comms triumph What we learned at PRWeek's Best Campaigns of 2015 Seminar Would you like to post a comment?Please Sign in or register.