Internet trolls pose a threat: Internet commentators shouldn’t be anonymous.

LONDON—If you are reading this article on the Internet, stop afterward and think about it. One group of researchers found that rude comments “not only polarized readers, but they often changed a participant’s interpretation of the news story itself.” A digital analyst at Atlantic Media also discovered that people who read negative comments were more likely to judge that an article was of low quality and, regardless of the content, to doubt the truth of what it stated. One Twitter campaigner, @AvoidComments, periodically reminds readers to ignore anonymous posters: “You wouldn’t listen to someone named Bonerman26 in real life. Last year Russian journalists infiltrated an organization in St. Petersburg that pays people to post at least 100 comments a day; an investigation this past summer found that a well-connected businessman was paying Russian trolls to manage 10 Twitter accounts with up to 2,000 followers. Perhaps schools, as they once taught students about newspapers, now need to teach a new sort of etiquette: how to recognize an Internet troll, how to distinguish truth from state- Sooner or later, we may also be forced to end Internet anonymity, or at least to ensure that every online persona is linked back to a real person: Anyone who writes online should be as responsible for his words as if he were speaking them aloud.