In this week's episode of Blogosphere: Serious Influence, Alice Audley (Blogosphere’s founder) speaks to Sir Martin Sorrell, who is the founder of S4 capital – a digital advertising and marketing services company established in May 2018.  S4’s strategy is to build a purely digital advertising and marketing services business by integrating leading businesses in three areas: first-party data, digital content and digital media planning and buying. Before S4 capital, Sir Martin was the chief executive of the world’s largest advertising and PR group WPP, which he founded in 1985 after taking a controlling stake in a small UK manufacturer of wire baskets and teapots called Wire and Plastic Products. Last year, Media Monks – S4 capital’s digital content arm merged with Amsterdam-based influencer-marketing network IMA.