Case Study: Reddit

Reddit is a social news aggregation and discussion website based in the United States. The platform has approximately 330 million monthly active users,¹ is ranked 16th for global internet engagement,² and has been labeled “the biggest little site no one’s ever heard of.”³ The platform enables users, who operate under pseudonyms, to create subpages, called subreddits, on specific interests or topics. In this way, the platform has become popular among particular interest or activity-focused communities, such as gamers and sports fans. The home page of Reddit, as well as each individual subreddit, uses a user-driven voting system that determines the ranking of content posted on each given page.⁴

Reddit utilizes a primarily decentralized and hybrid approach to content moderation. The company has a set of overarching content policies regarding acceptable content that are high-level and prohibit illegal content such as CSAM, as well as objectionable behaviors such as harassment and content that encourages or incites violence.⁵ In order to broadly enforce these content policies, Reddit has a small, centralized team of moderators (known to users as administrators or admins), who comprise approximately 10 percent of Reddit’s 400-person workforce.⁶ However, the majority of content moderation on the platform is carried out by the moderators of individual subreddits, who are known as mods. Mods are users who volunteer to moderate content on a particular subreddit. They have significant editorial discretion and can choose to remove content that violates Reddit’s rules or that they deem objectionable or off-topic. They can also temporarily mute or ban users from their subreddit. Mods are also empowered to create additional content policies that define acceptable content and use for their subreddits as long as they do not conflict with Reddit’s global set of content policies. All of the mods on a subreddit can also collectively create guidelines that outline their own responsibilities and codes of conduct. Mods may also have additional roles, such as fostering discussions, depending on the subreddit.⁷ Admins rarely intervene in content moderation decisions unless it is to remove objectionable content that is illegal or clearly prohibited by Reddit’s content policies,⁸ or to ban users from the site as a whole.⁹ According to researchers from Microsoft, there are approximately 91,563 unique mods on the platform, with an average of five mods per subreddit.¹⁰

By employing a decentralized approach to content moderation, Reddit is able to save time and resources by relying on its users to aid with content moderation. This approach keeps users engaged and serves the overall business aims of the company. In addition, it positions the company as a promoter of diverse viewpoints, since each individual subreddit has its own content policies that are tailored to the needs of each specific subreddit community.¹¹ This decentralized approach to content moderation has also resulted in users self-policing to ensure they do not violate specific content policies and has fostered an environment in which users call one another out for violating policies or posting objectionable content.¹² Further, this decentralized model enables localized and context-specific moderation decisions as mods set and enforce content guidelines that are appropriate to the particular nuances, norms, and variations attributed to different discussion topics.

“By employing a decentralized approach to content moderation, Reddit is able to save time and resources by relying on its users to aid with content moderation.”

In addition to employing a small number of human moderators to engage in ex-post reactive content moderation, Reddit admins also employ some automated tools in order to identify and remove objectionable content such as CSAM. However, because the majority of content moderation is carried out by users, Reddit has also developed an automated tool, known as the AutoModerator, that mods can use to moderate content on their subreddits at scale. The AutoModerator is a built-in, customizable bot that provides basic algorithmic tools to proactively identify, filter, and remove objectionable content during the ex-ante moderation stage. The bot operates based on mod-chosen parameters such as keywords, content that has a high number of reports, website links, and specific users, etc. that are not permitted in a particular subreddit. The AutoModerator can automatically remove this objectionable content, but mods also have the opportunity to review this removed content later and can reverse any erroneous removals. In addition to using the AutoModerator, many Reddit mods have turned to creating their own bots or tools, or using free versions available online, in order to flag custom words and enhance their moderation practices.¹³ The decentralized approach to content moderation empowers users to manage their own speech and helps democratize expression and enable localized and diverse viewpoints, as well as context-specific content moderation practices. However, it does raise a number of questions regarding accuracy and reliability, bias, and transparency and accountability. There is little insight into how accurate the AutoModerator is across different subreddits and categories of content or violations. In addition, because mods create the content policies for subreddits and define the parameters that the AutoModerator operates on, the deployment of automated tools for content moderation will undoubtedly reflect the personal biases of the mods. There is little transparency around this process, and because Reddit operates in a decentralized manner, there is a lack of a clear accountability mechanism.

In its transparency report, Reddit discloses the amount of content removed by mods—including through the use of the AutoModerator—and the amount of content removed by admins.¹⁴ However, this is the only metric that touches on the scope and volume of content moderation carried out by mods. The remainder of the metrics covered in the report, such as the number of potential content policy violations received, what percent of these reports were actionable, what content policies these actionable reports covered, and how many appeal requests were received and granted, are all admin-focused. Therefore, although the majority of content takedowns on Reddit involved removals by mods, most metrics in the report do not cover mod activities.¹⁵

The decentralized nature of Reddit’s content moderation approach therefore prevents further transparency around the activities of mods, who are responsible for moderating the most content, and how they are deploying algorithmic tools to manage and moderate user expression. Going forward, Reddit should consider requiring mods to monitor and track the amount of content they remove, both manually and using the AutoModerator, so the platform can disclose this information in its transparency report. In addition, Reddit offers notice to users who have had their content removed or accounts suspended. It also offers an appeals process to users who feel their content or accounts have been erroneously impacted by content moderation activities. However, it is unclear whether mods offer notices or a similar appeals processes to users who have been impacted by mods’ moderation processes. The AutoModerator, does, in fact, provide notice to users when it removes content from subreddits, suggesting that, when automated tools are deployed by mods to moderate content, users are notified of the resulting impact.¹⁶