Rory Cellan-Jones hears a call from leading ad industry executive Johnny Hornby, founder of The&Partnership, for Facebook and Google to help tackle fraud or risk facing a spending boycott. Plus he talks to Jeff Jarvis, journalism professor at the City University of New York about how advertising fuels fake news and how the media business needs to change to thrive alongside the big platforms. And Dan Faulkner, from voice recognition firm Nuance, chats about the day when your phone will not only answer your queries, but ask you questions back. With Zoe Kleinman from the BBC Online tech desk, and special guest Lara O'Reilly, senior editor at Business Insider who writes about advertising and media. (Image: Woman on sofa looking at an online advert, Credit: Getty Images).