When a guy with an assault rifle walks into a pizza joint to "self-investigate" the made-up conspiracy theory he found on the internet about a nonexistent child-prostitution ring, there's no doubt we've got a problem.
And regular folks are reasonably alarmed.
A new Pew Research Center study finds that two in three U.S. adults say that fabricated news stories cause "a great deal of confusion about the basic facts of current issues and events." This sense is shared widely across incomes, education levels, political affiliations and most other demographic characteristics, according to the study.
Pope Francis agreed, memorably comparing the consumption of fake news to the eating of excrement. (A much-shared fake story said he had endorsed Donald Trump for president.) President Barack Obama has chimed in on the dangers, too: "When there's so much active misinformation and it's packaged very well," he said, it poisons political discourse.
Facebook, initially reluctant to step into the fray, announced Thursday that it would take some first steps.