The internet’s video library Brendan Nyhan, the Dartmouth political scientist, worries less about unwitting users tumbling down rabbit holes than about small numbers of extremists who know what they’re looking for and find it by means of YouTube’s search function or by subscribing to channels dedicated to conspiratorial or hateful content. “I’m much more concerned about people who already have highly resentful views becoming more resentful or being mobilized to violent action or some kind of supporting [of] violent action,” Nyhan told us. In this sense, YouTube serves as the internet’s vast video library. Many users check out recipes, musical performances, or do-it-yourself tutorials. A small percentage—but one that may constitute a meaningful absolute number—looks for more alarming content. With his Dartmouth colleague Annie Y. Chen, Nyhan oversaw a study published in 2021 by the Anti-Defamation League that investigated racist or otherwise hateful channels on YouTube. They found little systemic evidence that the platform guided unsuspecting individuals to harmful content. Still, their data did “indicate that exposure to videos from extremist or white supremacist channels on YouTube remains disturbingly common.”43 In a separate report published in 2021, researchers with the Tech Transparency Project reinforced concerns about YouTube users who readily find the disturbing material they seek. When the Tech Transparency team used searches and other online behavior to simulate interest in militant themes, YouTube recomended videos such as, “5 Steps to Organizing a Successful Militia” and “So You Want to Start a Militia.”45 The danger lies not in the average user experience but the ability of people inclined toward extremism to easily find what they’re looking for or project violent intentions. Payton Gendron, the white 18-year-old accused of killing 10 African-American shoppers in a Buffalo, N.Y., grocery store in May, went to YouTube to watch videos about mass shootings, police gunfights, and tips on firearm use. It wasn’t until after the Buffalo massacre that YouTube removed three of the gun-related videos that Gendron mentioned in a diary.46 In another case, Frank James, who allegedly shot and wounded 10 people in a New York subway car in April 2022, had posted hundreds of videos of himself on YouTube and Facebook, many of them racist, threatening, and conspiratorial. In one YouTube video, James, an African American in his early 60s, said, “And so the message to me is: I should have gotten a gun, and just started shooting motherf—ers.”47 James’ videos didn't gain a large audience on YouTube. But Kate Starbird, the University of Washington researcher, points out that many YouTube users routinely copy the links of potentially harmful videos and plant them on other 'Young Turks': Commenters Advocate to '#ArmTheLeft' While right-leaning views dominate extreme content on YouTube, some creators on the left also promote polarization. The Young Turks (TYT) channel has nearly 5.2 million subscribers, making it “one of the most popular political coverage channels” on the platform, according to the London-based Institute for Strategic Dialogue (ISD). The mob attack on the U.S. Capitol in January 2021 elicited Super Chat comments on Young Turks that promoted “the use of firearms to achieve political aims,” according the ISD. One comment, which a Super Chat participant paid $20 to boost, included the hashtag “#ArmTheLeft.” Another called for the “arming and training” of “leftist militias.” One such channel is that of conspiracy theorist Mike Cernovich, a regular guest host of the far-right Alex Jones Show on the InfoWars website. Although YouTube had removed some highprofile channels before the study period in 2020—including that of former Ku Klux Klan leader David Duke—about one in ten subjects viewed at least one video from an extremist channel, the study found. More than two in ten viewed at least one video from a channel classified as “alternative,” meaning that it served as a potential gateway to more extreme far-right fare. Alternative YouTube channel hosts include Candace Owens, who has echoed Russian propaganda justifying the invasion of Ukraine.44 HOW YOUTUBE SPREADS HARMFUL CONTENT – AND WHAT CAN BE DONE ABOUT IT 9