The self-proclaimed ‘front page of the internet’, Reddit, has had a problem for a while with hate speech on its ‘subreddits’, the name given to communities on the site. The problem was so bad that an article was published by Mashable in 2014 claiming that ‘hate speech is drowning Reddit and no-one can stop it’. Several subreddits have been the subject of much controversy, including /r/FatPeopleHate, a subreddit dedicated to mocking the overweight and even posting fat-shaming photographs of the users’ colleagues and classmates, and an alt-right subreddit, /r/altright, which was openly racist and anti-Semitic.

But in 2015, when Ellen Pao, the former CEO of the site, announced a new initiative to clamp down on hate speech, she received significant backlash that contributed to her eventual resignation. Pao made the decision to ban subreddits that were particularly controversial (including Fat People Hate), introduced a new privacy policy to address reports of revenge porn on the site, and introduced new measures to avoid people being harassed on the site. She was met with accusations of censorship, and was told by some users of Reddit that she was naïve if she thought that people wouldn’t just migrate to other sites that allowed hate communities.

Two years later, Pao’s initiative has been vindicated by a new study by researchers from the Georgia Institute of Technology, Emory University, and the University of Michigan. The researchers focused on two hate subreddits, /r/FatPeopleHate and /r/CoonTown, and came to the conclusion that after the subreddits were banned, most users either left the site or had a dramatic decrease in the number of their comments that contained hateful content. The online communities that took in those who did leave the site did not experience an increase in the amount of hate speech.

The study also used a number of similar hate subreddits as controls, and found that most users who had been active on the subreddits that had been banned were not likely to migrate to similar subreddits to continue their posting. The study found a number of key terms associated with hate speech, and developed a ‘lexicon’ for each particular hateful subreddit. It was discovered that there was a decrease of between 80% and 90% of how often each lexicon was used across the site after the subreddit it was associated with was banned.

The backlash Reddit (and Pao in particular) faced when the ban was introduced was significant. A petition calling for Pao’s resignation was put onto the website change.org, and reached over 200,000 signatures. A similar website, Voat, claiming to be a free-speech friendly version received a sudden influx of users leaving Reddit. But according to the evidence, not many of these migrants became long-term users.

So, what does this mean for other sites that want to tackle hate speech? Well, the main take-away is that when communities that are spreading hatred are banned outright, the participants in those communities tend not to migrate elsewhere to make hateful comments, and the total amount of hate speech on the site decreases significantly. This study paves the way for websites like Facebook and YouTube to ban people creating hateful content, without the fear that outright bans are likely to simply drive them somewhere else.

Reddit’s initiative has proved that clamping down on hate speech works. The question is whether other websites are willing to take the bold necessary steps.