Should public media’s role on the internet be to make content for commercial platforms? Or should public media try to be the platform? The new RadioPublic mobile app is an attempt to do the latter. Last spring, Public Radio Exchange’s Jake Shapiro spun off from the organization he helped found in 2003 and started a new public benefit corporation “to build a mobile listening platform that makes listening to podcasts as simple as radio,” as set out in PRX’s announcement at the time. Well, now that platform is here. This week — as The Pub returns from hiatus — we take RadioPublic for a test drive with Shapiro and Matt MacDonald, RP’s chief product officer, and we talk about why they felt they had to leave the non-profit world in order to create it. Also this week, host Adam Ragusea uses the very silly new podcast he and his friend made about Billy Joel to make a vaguely serious point about how and when to insert clips into talk shows.