Large companies have slashed their digital marketing budget. Airbnb and Procter & Gamble made such a cut in recent years, after coming to believe the cost doesn’t necessarily translate to increased sales. They follow in the footsteps of eBay who, in 2013, announced it would cease paying for ad sponsorship on Google. Economics professor Steve Tadelis, who led eBay’s research into this, explains how they came to conclude advertising wasn’t worth it. Also in the programme, brand safety advocate and co-founder of Check My Ads Nandini Jammi explains how the modern digital ad market works, and where some doubts lay about its effectiveness. Luke Smith of marketing consultancy Croud says companies need to be clearer in what they want from digital marketing, in order to get the most out of it. But what if the market is overvalued as a whole? Former Google employee Tim Hwang, author of ‘Subprime Attention Crisis’ says we might be looking at an inflated market that could threaten a financial crash online.