Have you ever stumbled upon an hourlong online video of someone folding napkins? Or maybe crinkling paper, sorting a thimble collection, or pretending to give the viewer an ear exam? They’re called ...

The girl on screen runs her manicured nails over a shiny red lai see packet while whispering in hushed Cantonese. Her extra-sensitive microphone picks up every pop, tap and crackle from the paper ...