We all know YouTube. YouTube is the biggest video platform on the planet, with about 400 hours of video uploaded to the service every second.But YouTube, of all the current content "platforms," is arguably the most fragmented. There's no newsfeed, so there's no central place where everyone -- or seemingly everyone -- is gathering. As a result, communities form on their own, typically around channels or personalities, and they tend to be pretty insular.One of these communities formed around someone named Teal Swan. Swan is what you might call a "spiritual healer" or at least someone who believes herself to be that. But it turns out she has some very controversial thoughts on many topics, including suicide, and a lot of people think her teachings are potentially damaging — and may have contributed to the suicide of someone who followed her closely.That's exactly what Jennings Brown, a senior reporter at Gizmodo, investigated in The Gateway, a six-part podcast that explores the world of Swan, and how self-described "gurus" can use today's digital tools and platforms to reach massive audiences, and sometimes vulnerable people. Brown came on Mashable's MashTalk podcast to talk about his investigation and what he learned.What are the responsibilities of the platforms here? What about communities and individuals? And is there something mainstream services can glean about how these personalities cultivate loyal audiences? And how can we help the vulnerable navigate an at-times unforgiving digital culture?We take on those tough questions and more. But if you or someone you know is having suicidal thoughts, please call the National Suicide Prevention Lifeline at 800-273-8255 or text the Crisis Text Line at 741-741.