Most influencers, Bilton tells us—even, reportedly, mega-successful ones, like Kim Kardashian—have expedited their climb to the top of the social-media pyramid by purchasing followers, in order to inflate their engagement metrics. It’s in the best interest of social-media companies and their Wall Street investors to turn a blind eye to this practice, Bilton explains, as whirring stacks of hundred-dollar bills flash on the screen, because these puffed-up numbers equal increased proceeds. None of this is especially surprising, but as if not wanting to weigh viewers down, “Fake Famous” insists on leading them by the hand, occasionally descending to the tone of a cutesy explainer, à la the champagne-flute-brandishing, bathtub-soaking Margot Robbie in “The Big Short.” (At one point, Bilton notes that larger companies have access to “fancy software” that they use to determine the authenticity of influencers’ followers.)