left off, we look at two parts of what we learned there. the fact that it is the comments section that is in many ways the biggest issue and facebook can't control it. >> look, one thing we all have to understand about facebook, clicks, shares, likes and comments matter. they're the currency of facebook. the more reaction a post gets, in any of those forums, the more facebook's computers interpret the subject or the post as hot, interesting, lively, engaging, and, remember, everything about facebook is designed to maximize engagement, to keep us coming back, just like a casino, like a fruit machine in a casino. everything is designed to get us to want to keep interacting so we don't go off and watch youtube or go off and watch cnn. it is designed intentionally to do that. now, it wasn't designed for, like, public health emergencies