Social advertising: Evan Davis and guests discuss the growing power of celebrities, the rise of the money-making super-fans who "like" their products and the vloggers with consumer clout. How effective are these new social campaigns and how will they change the advertising industry?

Guests: Edwina Dunn, CEO Starcount; Dominic Burch, senior director marketing innovation and new revenue Asda; Robin Grant, co-founder We Are Social.

Producer: Rosamund Jones.