Parents and children have flocked to Google-owned YouTube Kids since it was introduced in early 2015. The app's more than 11 million weekly viewers are drawn in by its seemingly infinite supply of clips, including those from popular shows by Disney and Nickelodeon, and the knowledge that the app is supposed to contain only child-friendly content that has been automatically filtered from the main YouTube site. But the app contains dark corners, too, as videos that are disturbing for children slip past its filters, either by mistake or because bad actors have found ways to fool the YouTube Kids algorithms. In recent months, parents ... have complained that their children have been shown videos with well-known characters in violent or lewd situations and other clips with disturbing imagery, sometimes set to nursery rhymes. Many have taken to Facebook to warn others, and share video screenshots showing moments ranging from a Claymation Spider-Man urinating on Elsa of "Frozen" to Nick Jr. characters in a strip club. While the offending videos are a tiny fraction of YouTube Kids' universe, they are another example of the potential for abuse on digital media platforms that rely on computer algorithms, rather than humans, to police the content that appears in front of people - in this case, very young people. And they show, at a time when Congress is closely scrutinizing technology giants, how rules that govern at least some of the content on children's television fail to extend to the digital world.