Kaitlyn Tiffany

In 2015, the Southern Poverty Law Center called out Reddit as home to “the most violently racist” content on the internet, citing a constellation of antiblack forums, or subreddits, that had adopted the name “the Chimpire” and racked up tens of thousands of members before they were taken down that year. Reddit’s content policy prohibits inciting violence, as well as bullying and harassment, but it has never been very specific about where the lines are drawn.

On early Sunday morning, when the Dallas Police Department tweeted asking people to submit videos of “illegal activity” at protests to its iWatch Dallas app, K-pop fans were ready.“I wanted to do something to stop or slow [the police] down,” a 16-year-old Houston girl who goes by @YGSHIT on Twitter told me.