Not too long ago, the word “radio” meant something very particular: The turn of a knob to music stations cycling through the latest hits, or a Howard Stern/Rush Limbaugh-type spouting off, or an NPR member station, staidly delivering the news interspersed with occasional oddities like the musings of a horse born to be wind but trapped in his stable.1 Podcasts, meanwhile, were a subset of radio. Shows like This American Life, Radiolab, and 99% Invisible made their homes at public radio stations — WBEZ, WNYC, and KALW, respectively — but also distributed their episodes on iTunes, back when it was called that, so that anyone who had a smartphone but not a radio could listen in.