The best thing I heard all day was definitely Reply All's brand new upload, Decoders [April 21, 2016, 35 minutes]. Hosts PJ Vogt and Alex Goldman chat with reporter Rukmini Callimachi, a correspondent for The New York Times who covers the latest news on al-Qaeda and ISIS. They talk about the surprising ways their members use the internet to secretly (and sometimes not so secretly) communicate. It's fascinating. If you haven't heard it yet, I'd highly recommend adding it to your podcast queue immediately.