Misinformation, rumor, psy-ops and propaganda--whatever you want to call the four horsemen of today’s media apocalypse—have been with us as long as the media itself. But you have to admit that the arrival of digital technology, led by social media, has given all of those forces outsized power. We still haven’t quite come to terms with how tech has shattered things like a shared reality, democracy, civil discourse. That’s why today’s guest plays a key role in the journalism landscape. J...