If you’ve spent much time around the political world on social media, you may have noticed that some surnames mentioned in tweets or on blogs have a triple parentheses placed around them. You may have wondered what that was all about. They are called (((Echoes))).

It looks harmless, but it’s a 21st century version of the yellow Jewish star, intended to point out Jewish people on the internet by anti-Semitic trolls, many of whom are members of the alt-right. The notation functions as a clarion call for internet harassment, or, as one white nationalist called it, “closed captioning for the Jew-blind.” Unfortunately, many of those alt-right anti-Semites are rabid supporters of the Republican presumptive nominee, Donald Trump.

One Jewish writer who was on the receiving end of (((echoes))) trolling was Jonathan Weisman, deputy editor for the New York Times, who on May 26 tweeted a Washington Post story critical of Trump. He received a tweet from a poster calling himself @CyberTrump who taunted him with “Hello (((Weisman))).” When Weisman asked @CyberTrump to explain the symbol, the troll responded. “It’s a dog whistle, fool. Belling the cat for my fellow goyim.”

The parentheses symbol had its desired affect. It alerted fellow alt-right anti-Semites, who attacked Weisman relentlessly. “The anti-Semitic hate, much of it from self-identified Donald J. Trump supporters, hasn’t stopped since,” Weisman said. He also received a tweet which featured a picture of the gates of Auschwitz with its infamous slogan “Arbeit Macht Frei” replaced with “Machen Amerika Great.”