According to a new study by the Interactive Advertising Bureau, the American podcast industry brought in an estimated $314 million in advertising revenue in 2017, up 86% from the $169 million reported the year before. It beat projections established in the previous revenue study, which predicted that the ad business would grow to around $220 million in 2017. The study further predicts that podcast advertising will hit $659 million by 2020.   Other findings from IAB's podcast study:   Pre-produced ads make up a third of all ad types among the companies doing podcasts. Host-read ads make up the dominant remainder. In the podcasts that I've listened to, those host-read ads come off very effective. Usually they're at the beginning when the music has just ended, some playful banter has begun, and the atmosphere feels breezy—but in a good-content-to-come way.   Branded podcasts grew from 1.5% to 6.5% of all ad revenue between 2016 and 2017, disp ...