Social platforms—in their effort to keep users continually engaged (and targeted with relevant ads)—are designed to surface what’s popular and trending, whether it’s true or not. Since nearly half of web-using adults now get their news from Facebook in any given week, what counts as "truth" on our social platforms matters. When nonsense stories gain traction, they’re extremely difficult to correct. And stories jump from platform to platform, reaching new audiences and "going viral" in ways and at speeds that were previously impossible.