Reddit generally allows subreddit moderators to make editorial decisions about what content to allow. Many of the default subreddits are highly moderated, with the "science" subreddit banning climate change denialism, and the "news" subreddit banning opinion pieces and columns.
Reddit has changed its site-wide editorial policies several times, sometimes in reaction to controversies.
Reddit has historically been a platform for objectionable but legal content, and in 2011, news media covered the way that jailbait was being shared on the site before the site changed their policies to explicitly ban "suggestive or sexual content featuring minors".
Following some controversial incidents of Internet vigilantism, Reddit introduced a strict rule against the publication of non-public personally identifying information via the site (colloquially known as doxing). Those who break the rule are subject to a site-wide ban, which can result in the deletion of their user-generated content.
On Dec 16, a user named Matt posted a link describing how he had donated a kidney and included a JustGive link to encourage users to give donations to the American Cancer Society. After an initially positive reaction, Reddit users began to become suspicious of Matt's intentions and suggested that he was keeping the donations for himself. Users telephoned his home and he received death threats. Matt eventually proved that he was genuine by uploading his doctor's records.
On Oct 18, an IT manager submitted a post to the subreddit r/gameswap offering Redditors to trade one of 312 codes he had been given for the game Deus Ex: Human Revolution. A group of users obtained his personal details and began to blackmail him for the codes. Within days, he received 138 threatening phone calls both at home and at his job and had been fired by the end of the day.
- Following the Boston Marathon bombing in Apr, Reddit faced criticism after users wrongly identified a number of people as suspects. Notable among misidentified bombing suspects was Sunil Tripathi, a student reported missing before the bombings took place. A body reported to be Sunil's was found in Providence River in Rhode Island on Apr 25, according to Rhode Island Health Department. The cause of death was not immediately known, but authorities said they did not suspect foul play. The family later confirmed Tripathi's death was a result of suicide. Reddit general manager Martin later issued an apology for this behavior, criticizing the "online witch hunts and dangerous speculation" that took place on the website. The incident was later referenced in the season 5 episode of the CBS TV series The Good Wife titled "Whack-a-Mole", as well as The Newsroom.
- In late Oct, the moderators of the subreddit "r/politics" banned a large group of websites. Some were left-wing opinion websites, such as Mother Jones, HuffPost, Salon, AlterNet, Rawstory, The Daily Kos, Truthout, Media Matters, and ThinkProgress as well as some progressive blog sites, such as Democratic Underground and Crooks and Liars. They also banned a number of right-wing sites—Drudge Report, Breitbart, The Daily Caller, Dailypaul, Power Line, and Reason. Salon reported that "the section's moderators explained in a post on Tuesday, the goal is 'to reduce the number of blogspam submissions and sensationalist titles'". The purge, the moderators explained, is also aimed at sites providing much "bad journalism". The December list of banned websites has been modified since late October, and sites with original content, such as Mother Jones and The Huffington Post, are allowed. Moderators also banned RT, which moderators stated was due to vote manipulation and spam, though one moderator stated that he wanted RT banned because it is funded by the Russian Government.
In Aug, private sexual photos from the celebrity photo hack were widely disseminated across the site. A dedicated subreddit, "TheFappening", was created for this purpose, and contained links to most if not all of the criminally obtained explicit images. Some images of McKayla Maroney and Liz Lee were identified by redditors and outside commentators as child pornography because the photos were taken when the women were underage. The subreddit was banned on Sep 6. The scandal led to wider criticisms concerning the website's administration from The Verge and The Daily Dot.
- After Ellen Pao became CEO, she was initially a target of criticism by users who objected to the deletion of content critical of herself and her husband. Later on June 10, Reddit shut down the 150,000-subscriber "fatpeoplehate" subreddit and four others citing issues related to harassment. This move was seen as very controversial; some commenters said that the bans went too far, while others said that the bans did not go far enough. One of the latter complaints concerned a subreddit that was "expressing support" for the perpetrator of the Charleston church shooting. Responding to the accusations of "skewed enforcement", Reddit reaffirmed their commitment to free expression and stated, "There are some subreddits with very little viewership that get highlighted repeatedly for their content, but those are a tiny fraction of the content on the site."
- On July 2, Reddit began experiencing a series of blackouts as moderators set popular subreddit communities to private, in an event dubbed "AMAgeddon", a portmanteau of AMA ("ask me anything") and Armageddon. This was done in protest of the recent firing of Victoria Taylor, an administrator who helped organize citizen-led interviews with famous people on the popular AMA subreddit. Organizers of the blackout also expressed resentment about the recent severance of the communication between Reddit and the moderators of subreddits. The blackout intensified on July 3 when former community manager David Croach gave an AMA about being fired. Before deleting his posts, he stated that Ellen Pao dismissed him with one year of health coverage when he had cancer and did not recover quickly enough. Following this, a Change.org petition to remove Pao as CEO of Reddit Inc. reached over 200,000 signatures. Pao posted a response on July 3 as well as an extended version of it on July 6 in which she apologized for bad communication and not delivering on promises. She also apologized on behalf of the other administrators and noted that problems already existed over the past several years. On July 10, Pao resigned as CEO and was replaced by former CEO and co-founder Steve Huffman.
- In Aug, Steve Huffman introduced a policy that led to the banning of several offensive and sexual communities. Included in the ban was lolicon, to which Huffman referred as "animated CP [child porn]". Some subreddits had also been quarantined due to having "highly offensive or upsetting content" such as r/European, r/swedenyes, r/drawpeople, r/kiketown, r/blackfathers, r/greatapes, and r/whitesarecriminals.
- In May, Steve Huffman said in an interview at the TNW Conference that, unlike Facebook, which "only knows what [its users are] willing to declare publicly", Reddit knows its users' "dark secrets" at the same time that the website's "values" page was updated in regards to its "privacy" section. The video reached the top of the website's main feed. Shortly thereafter, announcements concerning new advertisement content drew criticism on the website.
- In Sep, a user named "Mormon documents" released thousands of administrative documents belonging to The Church of Jesus Christ of Latter-day Saints, an action driven by the ex-Mormon and atheist communities on Reddit. Previously, on Apr 22, the same user had announced his plans to do so. Church officials commented that the documents did not contain anything confidential.
- On Nov 23, Huffman admitted to having replaced his user name with the names of r/The_Donald moderators in many insulting comments. He did so by changing insulting comments made towards him and made it appear as if the insult were directed at the moderators of r/The_Donald.
- On Nov 24, The Washington Post reported Reddit had banned the "Pizzagate" conspiracy board from their site, stating it violated their policy of posting personal information of others, triggering a wave of criticism from users on r/The_Donald, who felt the ban amounted to censorship. The Reddit forum r/pizzagate was devoted to a widely-debunked conspiracy theory alleging that the Comet Ping Pong pizzeria in Washington, D.C. "is at the center of a child-abuse ring tied to John Podesta, Mrs. Clinton's former campaign manager". After the forum was banned from Reddit, the words "we don't want witchhunts on our site" now appear on the former page of the Pizzagate subreddit.
- On Nov 30, Huffman announced changes to the algorithm of Reddit's r/all page to block "stickied" posts from a number of subreddits, such as r/The_Donald. In the announcement, he also apologized for personally editing posts by users from r/The_Donald, and declared intentions to take actions against "hundreds of the most toxic users" of Reddit and "communities whose users continually cross the line".
On July 12, the creator and head moderator of the GamerGate subreddit, r/KotakuInAction, removed all of the moderators and set the forum to private, alleging it to have become "infested with racism and sexism". A Reddit employee restored the forum and its moderators an hour later.
- In Jan, the Filipino-themed subreddit r/jakolandia was accused of "distributing” posts of photos of women, including celebrities, apparently without their consent, similar to "a number" of secret Facebook groups that had been engaging in illegal activity of sharing "obscene" photos of women and possibly child pornography.
- In Feb, Chinese company Tencent invested $150M into Reddit. This resulted in a large backlash from Reddit users, who were worried about potential censorship. Many posts featuring subjects censored in China, such as Tiananmen Square, Tank Man, and Winnie the Pooh, received popularity on Reddit.
- During the George Floyd protests in early June, over 800 moderators signed an open letter demanding a policy banning hate speech, a shutdown of racist and sexist subreddits, and more employee support for moderation. Bloomberg News pointed out the company's slow reaction to r/watchpeopledie, a subreddit dedicated to videos of people dying in accidents and other situations, and the harassment that accompanied new unmoderated features like icons for purchase and public chats.
- On Jun 29, Reddit updated its content policy and introduced rules aimed at curbing the presence of communities they believed to be "promoting hate", and banned approximately 2,000 subreddits that were found to be in violation of the new guidelines on the same day. Larger subreddits affected by the bans included r/The_Donald, r/GenderCritical (the platform's largest and most active anti-transgender radical feminist subreddit), and r/ChapoTrapHouse (a far-left subreddit originally created by fans of the podcast Chapo Trap House). Some media outlets and political commentators also condemned the banning of the r/The_Donald and r/ChapoTrapHouse subreddits as a violation of the right to free political expression.
- On Aug 3, moderators of the subreddit r/Animemes banned the usage of the word "trap" to refer to any person or fictional character. The ban was predicated on the real-world usage of the word "trap" as a slur against transgender people, with moderators citing the trans panic defense. In response, many users of the subreddit contended that "trap" was not being used in a transphobic manner, but instead to endearingly refer to cross-dressers, otokonoko, and characters with related identities in animanga. Many users flooded the subreddit with memes making fun of the rule change and the moderation team. Many left in protest, which resulted in a loss of over 100,000 subscribers.
- After the 2021 storming of the United States Capitol, Reddit announced that it had banned the subreddit r/DonaldTrump in response to repeated policy violations and alluding to the potential influence the community had on those who participated in or supported the storming. The move followed similar actions from social media platforms, Twitter, YouTube, TikTok, and more. The ban brought controversy from those who believed it furthered an agenda and censorship of conservative ideologies. The subreddit had over 52,000 members just before it was banned.
- In Mar, Reddit users discovered that Aimee Challenor, an English politician who had been suspended from two UK political parties, was hired as an administrator for the site. Her first suspension from the Green Party came for retaining her father as her campaign manager after his arrest on child sexual abuse charges. She was later suspended from the Liberal Democrats after tweets describing pedophilic fantasies were discovered on her partner's Twitter account. Reddit banned a moderator for posting a news article that mentioned Challenor, and some Reddit users alleged that Reddit was removing all mention of Challenor. A large number of subreddits, including r/Music which had 27 million subscribers, and 19 other subreddits with over 1 million subscribers, went private in protest. On Mar 24, Reddit's CEO Steve Huffman said that Challenor had been inadequately vetted before being hired and that Reddit would review its relevant internal processes. He attributed user suspensions to over-indexing on anti-harassment measures. Challenor was also removed from her role as a Reddit admin.