Note: This episode contains strong language. Today, we’re sharing Episode 3 of “Rabbit Hole,” a New York Times audio series with the tech columnist Kevin Roose.In this episode, our reporter continues to trace the journey of a young man named Caleb. Five years into a rabbit hole on YouTube, Caleb discovers a parallel universe.If you're tuning in to "Rabbit Hole" for the first time, start with the prologue. For more information on today’s episode, visit nytimes.com/rabbithole.