

Dawson, whose real name is Shane Lee Yaw, has more than 20 million subscribers and a devoted teenage fan base. In late January, the company announced that it was changing its recommendations algorithm to reduce the spread of “borderline content and content that could misinform users in harmful ways.” It cited, as examples, “videos promoting a phony miracle cure for a serious illness, claiming the earth is flat or making blatantly false claims about historic events like 9/11.” Dawson’s conspiracy series arrived at a particularly awkward moment for YouTube, which has been reckoning with the vast troves of misinformation and extreme content on its platform. Cheese’s, the restaurant chain, which was forced to deny claims that it recycles customers’ uneaten pizza slices into new pizzas. A follow-up has drawn more than 20 million views and started a public feud with Chuck E. The video has gotten more than 30 million views, a hit even by Mr. None of this was fact-based, of course, and some of the theories seemed more like jokey urban legends than serious accusations.

Among them: that iPhones secretly record their owners’ every utterance that popular children’s TV shows contain subliminal messages urging children to commit suicide that the recent string of deadly wildfires in California was set on purpose, either by homeowners looking to collect insurance money or by the military using a type of high-powered laser called a “directed energy weapon.” Dawson unspooled a series of far-fetched hypotheses. In the video, set to a spooky instrumental soundtrack, Mr. Last month, the YouTube star Shane Dawson uploaded his new project: a 104-minute documentary, “Conspiracy Theories With Shane Dawson.”
