If you stumbled onto Reddit some midsummer’s morning, here’s what you might have found on the self-styled “front page of the Internet”: A local news article about Donald Trump’s latest faux pas. A photo of several dozen people watching Jaws while floating on inner tubes. More than 2,600 comments parsing the question “When did you discover that you were hot?” An animated GIF of Shaq dunking a golf ball. And a video of a torpid cat ruining some poor woman’s yoga practice. Obviously.

This is the kind of fare that makes Reddit.com the 10th most trafficked website in the U.S., eclipsing Netflix, Pinterest and the New York Times, according to Internet tracker Alexa. Its 164 million mostly young, mostly male users generated more than 7 billion page views in June, posting links and comments, then voting them up or down to surface the most thought-provoking, salacious or funny. Unlike other web aggregators such as BuzzFeed or ViralNova, Reddit is home to a community that routinely takes action in the real world. Often these campaigns have noble aims, like the successful 2014 drive to find one user’s elderly father, who, ill and confused, had wandered off. Or the 2012 episode in which Reddit shut itself down in protest of proposed congressional legislation that many users felt violated the principles of a free Internet.

But sometimes they can be mean-spirited, bullying or dangerous, like the time Reddit users misidentified a man as the Boston Marathon bomber, fueling inaccurate media speculation and terrorizing his family in the process. (The man had disappeared before the bombing and, it was later discovered, had committed suicide.) Then there’s the really dark side, threads like “Self Harm Pics” or “Cute Female Corpses,” both exactly as disturbing as they sound. “Reddit reflects the Internet, and the Internet reflects humanity,” says co-founder Alexis Ohanian. “Unfortunately, humanity is always going to have jerks.”

What some of those jerks do has more influence on your daily media intake than you might think. There’s a trickle-down effect to what’s happening on Reddit: memes that take root there become blog posts, which become trending hashtags on Twitter, which become morning-television fodder, which become your mom’s Facebook post and so on, snaking their way forward into our lives.

Founded a decade ago–making it roughly ancient in startup years–Reddit became a vital organ of the Internet in large part because as a unit of Advance Publications it was unencumbered by the demands of venture capitalists. The company was spun off in 2011 and late last year raised funds reportedly valuing it at $500 million. Now it must decide whether to cast its lot with the Twitters and Facebooks of the world, by attempting to turn its huge and addicted audience into a captive-for-advertisers’-benefit one, or remain the barely commercial but wildly successful free-for-all that helps define current Internet culture.

Since late last year, Reddit has been run by Ohanian, 32, now the company’s chairman, and interim CEO Ellen Pao, probably best known for her unsuccessful gender-discrimination lawsuit against venture-capital firm Kleiner Perkins Caufield & Byers, which disrupted Silicon Valley like a meteor hitting a country barn. Over the past few months, the pair have banned “involuntary pornography,” bullying behavior and other unseemly content. “I want to get Reddit to 1 billion users,” says Ohanian. But that isn’t likely to be easy, because Reddit is disposed to periodic crises—the latest of which came out of nowhere late on the evening of July 2, when some of the website’s followers nearly brought the whole contraption down.

Reddit was created by Ohanian and Steve Huffman. The two met as college freshmen at the University of Virginia. Huffman, who lived across the hall from Ohanian, expected a girl to show up when he saw the name Alexis on the opposite door. “My first memory of Alexis is disappointment,” he jokes. Huffman was a to-the-point computer-science type. Ohanian, who’d grown up an only child in Maryland tinkering with PCs, was the showman, cutting his teeth giving demonstrations in a local CompUSA. “Alexis is a bon vivant, and Steve’s a little more serious,” says Sam Altman, a current Reddit board member who was one of the site’s first 10 users and met its founders early on. “They were a very good complement to each other, and that was powerful.”

In 2005 their idea for a web aggregator in the mold of the then popular Del.icio.us got $12,000 in seed funding as part of Y Combinator, an influential tech incubator founded the same year. After graduating, Ohanian and Huffman moved into a small two-bedroom apartment in Medford, a suburb of Boston. For the better part of a month, they rarely left the un-air-conditioned space, aside from the occasional pizza run. Every morning, Huffman and Ohanian would listen to the hit song of that summer, “Hollaback Girl” by Gwen Stefani, sit down at opposing monitors and work from 10 a.m. until 11 p.m. “Then we’d play World of Warcraft until 3 a.m. and start all over again the next day,” recalls Ohanian. Sometimes they took meetings in the kitchen for a change of scenery, Huffman notes.

Reddit—the name is a phonetic contraction, as in “I read it on”—launched on June 23, 2005. Unlike Wikipedia, which is strictly policed by a relatively small number of editors, Reddit is self-governed: Users, or Redditors as they’re called, can post links or threads on any topic, often consisting of stuff they collect or create themselves. Then others vote them up or down. The site relies to a large extent on the goodwill—and free labor—of the moderators who keep the community humming. Threads that generate the most up votes populate the site’s front page, a reflection of the Internet’s obsessions and interests at any given moment. There are more than 9,000 active subreddits, or single-topic communities, about everything from knitting (more contested territory than you might think) to photos of animals being jerks (pretty standard) to My Little Pony (bizarre).

A lot of Reddit’s character, light and dark, comes from the anonymity of its users. Unlike Facebook, which moored us all online to our real identities, Redditors can talk about pretty much anything openly. That’s why teens use it to discuss the difficulty of coming out, why it’s a favored tool of dissident hackers and also why auto-body mechanics feel comfortable posting pictures of what their most clueless customers have done to their cars through miscare. “I would argue, for a lot of people, their real identity is on Reddit,” says Ohanian. “Reddit is going to continue growing because people are desperate for the authenticity that it allows.”

Some of the site’s most active communities include Ask Reddit, in which users pose open questions such as “What ideas hold society back?” and “What discontinued item do you miss the most?” These are often filled with poignant responses, sometimes thousands deep. Another is Ask Me Anything, or AMA for short, in which people of varied backgrounds answer questions from the audience. These have included the puppeteer behind Big Bird, a man with two penises and, in 2012, President Obama. These days Reddit is such a draw, it’s likely to become an unavoidable whistle-stop during the 2016 presidential election, much as The Daily Show did a few cycles past.

There’s something haphazard about all this success, because in 2006, some 18 months after founding the site, Huffman and Ohanian sold the company to Advance Publications for an undisclosed sum, agreeing to stay on as part of the Condé Nast magazine empire’s digital network. “The idea of becoming a millionaire at 23—I didn’t want to live regretting that,” says Ohanian.

But afterward Reddit entered a kind of fallow period. Though the number of users continued to steadily grow, Reddit never made the costly and painful transition to the mobile Internet. And the site’s front page doesn’t look radically different from how it did a decade ago. “There’s no doubt the site took a meandering path,” says Altman of this period. Reddit was still alive throughout the social-media boom, but it was effectively frozen in carbonite like Han Solo. Until last year.

Reddit’s new, post-spin-off offices are located in a nondescript brick building on New Montgomery Street in downtown San Francisco. There’s no sign on the door, for “security purposes,” I’m told. Inside, there’s a large open space with several dozen young people quietly working behind big monitors. The walls are decorated with graffiti-style murals designed by local artists, some riffing on popular Reddit themes (robot chickens, trippy abstract patterns) or the site’s alien mascot, nicknamed Snoo, derived from “what’s new.” “Our job now is to bring out the positive side of Reddit, the goodness of Reddit,” says CEO Pao, who is sitting under a giant, tumbling illustration of Calvin and Hobbes with a speech bubble that reads, “It’s morning, we can do stuff again!”

Pao, 45, is a controversial figure in Silicon Valley. The civil trial in which Pao alleged systematic gender bias after ending a sexual relationship with a Kleiner partner was closely followed and generated palpable soul-searching among technology companies about gender and racial bias. (She declines to comment on her appeal of the verdict, which is ongoing.) The stock photo commonly used alongside articles about the trial showed Pao arms crossed and tight-lipped. But in person she’s warm and funny and smiles a lot, especially when trying to choose her words delicately.

Pao, who sits at a small desk in the middle of the floor, has poached executives from Facebook, Google and Snapchat, among others, to bulk up sales, operations and especially engineering. To keep the site growing, she is planning to introduce Reddit’s first mobile app later this year. Pao expects 90% of the site’s traffic to come from mobile in the next two years, up from 45% today.

A bigger challenge is revenue. The company brought in just $8.6 million from ads last year. Though a small number of dedicated users pay a $3.99 monthly membership fee (Reddit won’t say how many), the majority of revenue comes from advertising. Most of that is traditional ads, but Pao and her new head of sales, Zubair Jandali, are increasingly trying to get advertisers—Nissan and Marriott, among others—to use the site the way Redditors do, hosting conversations related to a particular topic.

Pao is also trying to guide Reddit through its periodic upheavals, like the one that helped make her CEO. In August 2014, Redditors posted naked pictures that were stolen from celebrities’ Apple iCloud accounts. Though photos of victims like Jennifer Lawrence and Kate Upton first appeared on 4Chan, a subreddit called the Fappening became a hub for disseminating them. Administrators moved to shut the thread down but only after offering a confusing set of reasons.

Reddit’s former CEO, Yishan Wong, was criticized for botching the site’s response and left shortly after. Ohanian, who had left with Huffman in 2009 to help launch travel site Hipmunk, was called back in as chairman. Pao, who had been consulting with the company on partnerships and strategy, was installed as CEO. Her interim status is due, in part, to the emergency nature of her appointment. Altman, the board member who installed them both, thought the pair would work because Ohanian has a “founder’s authority” with the community and Pao is equipped to make other hard choices.

A lot of those are likely to consist of policies such as the ones backed in May in the wake of the Fappening fracas. Reddit administrators began deleting abusive threads, including one centered on body shaming, as part of the site’s new antiharassment policy. Retaliatory threads comparing Pao to Hitler and calling for her resignation quickly shot to the front of the Reddit home page. “It’s the Internet,” says Pao of the personal attacks, “and something I’ve been dealing with for a year. I just ignore it.”

Ohanian adds that the bans are an attempt to protect Reddit on the whole: “We will do anything to preserve the ecosystem, and that type of [content] is a threat to the ecosystem.” He describes the policies, more of which are likely in the future, as “scalpels” intended to excise only the worst behavior without impinging on the site’s commitment to free speech. “At some 170 million people, we’re really talking about tens of thousands doing bad.”

Ohanian and Pao are trying to double down on the mainstream, even as the site’s most avid users grow weary of change. To help make Reddit more accessible, they are launching a slate of original programming such as a weekly newsletter and a series of video AMAs. The first one features popular astrophysicist Neil deGrasse Tyson musing about which planet he’d most like to be painted on in the nude (Mars) and is scheduled to go on the site in July. All of this is aimed, says Pao, at “helping people understand what Reddit actually is.”

What Reddit actually is was being hotly debated once again early this month as the site descended into yet another turn of chaos. After the surprise dismissal of a popular employee, Victoria Taylor, Reddit’s director of talent and an AMA facilitator, on July 2, moderators revolted. In protest, they shut down more than 1,800 subreddits, according to a moderator who posted a list. For two days the site blinked on and off like a dying radio as Ohanian fielded questions online and made phone calls to moderators into the middle of the night. Google searches for “Reddit alternative,” as one thread on the home page pointed out, spiked. An online petition calling for Pao to resign quickly reached over 200,000 signatures.

Ultimately, Pao apologized. “We handled the transition in a way that caused some disruption,” she says, “and we should have done a better job.” But her apology seems unlikely to appease angry moderators. Writing in a July 8 New York Times op-ed, Brian Lynch and Courtnie Swearingen, two Reddit moderators, argued that “Ms. Taylor’s sudden termination is just the most recent example of management’s making changes without thinking through what those changes might mean for the people who use the site on a daily basis.” Though the site is more or less back to normal, the chorus of users calling for Pao’s firing goes on.

But the episode shows the unique and delicate position Reddit is in at the moment. Companies like Google, which early on trumpeted a “Don’t be evil” motto, and Twitter, which originally billed itself as the ” free-speech wing of the free-speech party,” have had to make adjustments as their businesses grew and it became clear they were moneymaking ventures, not graduate-school theses.

Reddit, on the other hand, has to be seen by users as true to its ideals—or they may shut down the site in protest or leave altogether. What’s more, the stakes of Reddit’s principles are much greater than something vague like, “Don’t be evil.” For one, free speech is a more concrete idea. For another, the site’s users are deeply invested in that idea and apparently willing to disrupt Reddit’s operation in order to maintain their version of it.

In the relatively short history of the Internet there have been a number of influential sites that ultimately failed. MySpace, LiveJournal and the early social network Orkut come to mind. Some bombed as businesses, others collapsed as communities. The difference is that a great part of Reddit’s appeal lies in its users’ awareness of their own power. How it navigates its current turmoils is beside the point. What happens may show us how compatible near total free speech really is with the Internet, or at least the moneymaking part of the Internet.

None of this seems lost on Ohanian. “We have no site without our users,” he says, smiling and waving his hand toward the rest of the Reddit offices. “We’re just the janitors here.”

This appears in the July 20, 2015 issue of TIME.

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