Reddit had a problem. Perhaps more accurately, the Internet has long had a problem, but in 2015 Reddit attempted to do something about their corner of it.
Now two years after the popular online community board made a controversial decision to close down some of some of its more hateful spaces, a study has shown it successfully reduced the amount of hate speech being communicated on the entire site.
Researchers from Georgia Institute of Technology, Emory University, and University of Michigan analysed over 100 million posts and comments on the website in the wake of Reddit's mid-2015 removal of a number of boards called subreddits.
Subreddits are the conference rooms of the website, with some of the one million user-generated rooms attracting as many as 18 million subscribers, not to mention a constant stream of Internet pedestrians.
While Reddit has a content policy, and an army of subreddit administrators to help enforce it, the website was seen as broadly tolerant of what constitutes a reasonable topic for discussion.
Many have celebrated Reddit's limited constraints. But in recent years website stakeholders have become increasingly concerned over a growing tide of harassment that – putting it plainly – compromised wellbeing and a sense of safety among users, and dissuaded new users from joining.
The banning of a selection of subreddits was a key part of an anti-harassment policy handed down by interim CEO Ellen Pao.
The move targeted communities that explicitly encouraged expressions of hate and discrimination towards certain demographics, such as the overweight or ethnic populations.
The decision was by no means celebrated by everybody – there were calls for Pao's resignation over fears it was the start of a slippery slope that heralded further censorship, concerns it was too selective and inconsistent, and arguments it flew in the face of free speech.
Threads appeared discussing the ban, with a number of Reddit users doubting it would work, suggesting the harassment would simply pop up again under another name.
With this new study comes some hard evidence to throw into the debate. It turns out many of the criticisms are unfounded.
To determine changing patterns of hate speech, the researchers created and ranked a lexicon that defined boundaries and helped establish a metric.
The team also identified a number of subreddits based on similar topics that weren't closed, to use as controls in identifying a cohort of active banned subreddit users.
They found that post-closure, a significant number of banned subreddit contributors simply stopped posting on the website altogether.
Meanwhile, not all of those who stuck took their hate speech elsewhere, with an 80 to 90 percent reduction in use of terms included in the lexicon across the website.
While many users did migrate to post more frequently in forums where discriminatory behaviours had already been noted as prevalent, there was no significant change in the amount of hate speech in either the user or the subreddit.
"In simpler terms, the migrants did not bring hate speech with them to their new communities, nor did the longtime residents pick it up from them," the researchers write. "Reddit did not 'spread the infection.'"
The shift in word prevalence doesn't necessarily point to a simple cause, so we need to be cautious before concluding the closure of the more toxic subreddits was directly responsible for reducing the visibility of hateful language.
Social forces can be complex to build rules around, so we can only speculate on the role of established social values in modifying individual behaviours.
"Perhaps existing community norms and moderation policies within these other, well-established subreddits prevented the migrating users from repeating the same hateful behaviour," the researchers suggest.
While it's not a solid blueprint on how to handle hate-speech, the study should help other stakeholders in social media platforms predict the potential consequences of closing down forums.
There are still the usual questions to debate as well, such as how to combine tolerance for diverse views with intolerance over language that actively harms and excludes.
But whatever course of action we take in striking that balance, having good data is vital.
This research was published in the Proceedings of the ACM on Human-Computer Interaction.