Audio: Listen to this story. To hear more feature stories, download the Audm app for your iPhone.

Which Web sites get the most traffic? According to the ranking service Alexa, the top three sites in the United States, as of this writing, are Google, YouTube, and Facebook. (Porn, somewhat hearteningly, doesn’t crack the top ten.) The rankings don’t reflect everything—the dark Web, the nouveau-riche recluses harvesting bitcoin—but, for the most part, people online go where you’d expect them to go. The only truly surprising entry, in fourth place, is Reddit, whose astronomical popularity seems at odds with the fact that many Americans have only vaguely heard of the site and have no real understanding of what it is. A link aggregator? A microblogging platform? A social network?

To its devotees, Reddit feels proudly untamed, one of the last Internet giants to resist homogeneity. Most Reddit pages have a throwback aesthetic, with a few crudely designed graphics and a tangle of text: an original post, comments on the post, responses to the comments, responses to the responses. That’s pretty much it. Reddit is made up of more than a million individual communities, or subreddits, some of which have three subscribers, some twenty million. Every subreddit is devoted to a specific kind of content, ranging from vital to trivial: r/News, r/Politics, r/Trees (for marijuana enthusiasts), r/MarijuanaEnthusiasts (for tree enthusiasts), r/MildlyInteresting (“for photos that are, you know, mildly interesting”). Some people end up on Reddit by accident, find it baffling, and never visit again. But people who do use it—redditors, as they’re called—often use it all day long, to the near-exclusion of anything else. “For a while, we called ourselves the front page of the Internet,” Steve Huffman, Reddit’s C.E.O., said recently. “These days, I tend to say that we’re a place for open and honest conversations—‘open and honest’ meaning authentic, meaning messy, meaning the best and worst and realest and weirdest parts of humanity.”

On November 23, 2016, shortly after President Trump’s election, Huffman was at his desk, in San Francisco, perusing the site. It was the day before Thanksgiving. Reddit’s administrators had just deleted a subreddit called r/Pizzagate, a forum for people who believed that high-ranking staffers of Hillary Clinton’s Presidential campaign, and possibly Clinton herself, were trafficking child sex slaves. The evidence, as extensive as it was unpersuasive, included satanic rituals, a map printed on a handkerchief, and an elaborate code involving the words “cheese” and “pizza.” In only fifteen days of existence, the Pizzagate subreddit had attracted twenty thousand subscribers. Now, in its place, was a scrubbed white page with the message “This community has been banned.”

The reason for the ban, according to Reddit’s administrators, was not the beliefs of people on the subreddit, but the way they’d behaved—specifically, their insistence on publishing their enemies’ private phone numbers and addresses, a clear violation of Reddit’s rules. The conspiracy theorists, in turn, claimed that they’d been banned because Reddit administrators were part of the conspiracy. (Less than two weeks after Pizzagate was banned, a man fired a semiautomatic rifle inside a D.C. pizzeria called Comet Ping Pong, in an attempt to “self-investigate” claims that the restaurant’s basement was a dungeon full of kidnapped children. Comet Ping Pong does not have a basement.)

Some of the conspiracy theorists left Reddit and reunited on Voat, a site made by and for the users that Reddit sloughs off. (Many social networks have such Bizarro networks, which brand themselves as strongholds of free speech and in practice are often used for hate speech. People banned from Twitter end up on Gab; people banned from Patreon end up on Hatreon.) Other Pizzagaters stayed and regrouped on r/The_Donald, a popular pro-Trump subreddit. Throughout the Presidential campaign, The_Donald was a hive of Trump boosterism. By this time, it had become a hermetic subculture, full of inside jokes and ugly rhetoric. The community’s most frequent commenters, like the man they’d helped propel to the Presidency, were experts at testing boundaries. Within minutes, they started to express their outrage that Pizzagate had been deleted.

Redditors are pseudonymous, and their pseudonyms are sometimes prefaced by “u,” for “username.” Huffman’s is Spez. As he scanned The_Donald, he noticed that hundreds of the most popular comments were about him:

“fuck u/spez”

“u/spez is complicit in the coverup”

“u/spez supports child rape”

One commenter simply wrote “u/SPEZ IS A CUCK,” in bold type, a hundred and ten times in a row.

Huffman, alone at his computer, wondered whether to respond. “I consider myself a troll at heart,” he said later. “Making people bristle, being a little outrageous in order to add some spice to life—I get that. I’ve done that.” Privately, Huffman imagined The_Donald as a misguided teen-ager who wouldn’t stop misbehaving. “If your little brother flicks your ear, maybe you ignore it,” he said. “If he flicks your ear a hundred times, or punches you, then maybe you give him a little smack to show you’re paying attention.”

“He’s unbeatable on carpet.” Facebook

Twitter

Email

Shopping

Although redditors didn’t yet know it, Huffman could edit any part of the site. He wrote a script that would automatically replace his username with those of The_Donald’s most prominent members, directing the insults back at the insulters in real time: in one comment, “Fuck u/Spez” became “Fuck u/Trumpshaker”; in another, “Fuck u/Spez” became “Fuck u/MAGAdocious.”

The_Donald’s users saw what was happening, and they reacted by spinning a conspiracy theory that, in this case, turned out to be true.

“Manipulating the words of your users is fucked,” a commenter wrote.

“Even Facebook and Twitter haven’t stooped this low.”

“Trust nothing.”

The incident became known as Spezgiving, and it’s still invoked, internally and externally, as a paradigmatic example of tech-executive overreach. Social-media platforms must do something to rein in their users, the consensus goes, but not that.

Huffman can no longer edit the site indiscriminately, but his actions laid bare a fact that most social-media companies go to great lengths to conceal—that, no matter how neutral a platform may seem, there’s always a person behind the curtain. “I fucked up,” Huffman wrote in an apology the following week. “More than anything, I want Reddit to heal, and I want our country to heal.” Implicit in his apology was a set of questions, perhaps the central questions facing anyone who worries about the current state of civic discourse. Is it possible to facilitate a space for open dialogue without also facilitating hoaxes, harassment, and threats of violence? Where is the line between authenticity and toxicity? What if, after technology allows us to reveal our inner voices, what we learn is that many of us are authentically toxic?