Inspired by Agassi's groundbreaking 2009 memoir—a raw portrait of insecurity and searching in which the former world tennis champion admits to everything from using crystal meth to hating the game, so unusual The New York Times dubbed it "one of the most passionately anti-sports books ever written by a superstar athlete"—Jeter decided to take such openness and transform it into an industry. In 2014, along with Jaymee Messler, a marketing officer at his former sports agency, Jeter launched The Players' Tribune, a website devoted to allowing athletes to tell their own stories on whatever topics they wanted. He invited colleagues including Kobe Bryant, David Ortiz and Danica Patrick to open up about issues such as depression, politics and overcoming fear in games. What made this groundbreaking twist in sports media all the more surprising? Many consider its creator the least talkative person in sports. For 20 years, Jeter, 43, was renowned for being a blank slate under the harsh media spotlight, the star slugger who never said anything revealing or scandalous. From the outside, it seemed as if Jeter was carefully crafting his image, a political mastermind manipulating journalists with his studied silence. Jeter, however, claims otherwise. "People say I always gave the same answers to reporters," he says. "Well, I always got the same questions. So the idea behind The Players' Tribune was to create a space for athletes to share their interests and beliefs outside of the arena. We're not just one-dimensional. And now the amazing thing is that athletes are coming to us on their off days to brainstorm ideas. These are stories we're only now beginning to tell."

Founded in 2014, The Players' Tribune has grown rapidly from a Manhattan rental office with little more than a whiteboard to a revolutionary force in the media world with $58 million in funding and new offices in Los Angeles, London and Barcelona. Its success is due in large part to a forward-thinking business model focused on high-quality branded content. As an advertising platform, branded content (companies underwriting stories as a means of marketing) has been around since the 1940s, back when businesses like Texaco and Lucky Strike cigarettes sponsored TV and radio programs. In 2001, BMW updated the format for the internet era with the groundbreaking online film series "The Drive". Starring Clive Owen as a mysterious driver transporting people around the world, the series scored over 100 million views and snagged awards at Cannes. In 2013, Dove took the medium a step further with "Real Beauty Sketches," a video program examining perceptions of beauty by women that got more than 180 million views and made headlines for its thought-provoking content. In all of these instances, the logos and products of the underwriting companies were barely visible, if at all—the ads were meant to simply engage the viewer, drawing them into the broader world of the businesses' values while leaving a subtle but powerful impression of the brand in the process. "Branded content is a nontraditional way of advertising," says Tulin Erdem, a professor of marketing at NYU Stern. "It's not a direct selling proposition. It's more about the brand's promise, its positions and causes in society. It works because in a very crowded marketplace you have to create a message that resonates with consumers, that makes them think. This is difficult with a quick TV spot orientated to mass consumers. But with branded content you can truly engage, which is why we're starting to see more and more of it now."

In the world of branded content, The Players' Tribune represents a new wrinkle, as the company bases its revenue almost entirely on the creation of high-quality sponsored stories, following a game plan intended to leverage its greatest asset: the athletes. If the key to making powerful branded content is to engage the readers' emotions—to make them feel something and then hopefully associate that feeling with your brand—then sports is a natural fit. Last June, the site hired its first CEO, Jeff Levick, the former CRO of Spotify, who has also held marketing stints at Google and AOL. A veteran of disruptive companies, Levick sees The Players' Tribune as creating its own category in the media space, appealing to fans in the same way he saw musicians impact listeners at Spotify. "For me, The Players' Tribune is like looking at what I had seen in the tech world—a unique revenue model," Levick says. "This was a space that had yet to be disrupted in media, a site centered around a unique class of content creators that had never existed before—the athletes."

At the loft-like Players' Tribune offices on the west side of Manhattan, editors and videographers huddle around workstations, the scene similar to any other major media company. But instead of creating their own content, The Players' Tribune staff is helping an endless rotation of visiting athletes tell their stories in a range of formats from articles to videos to podcasts. The resulting pieces will ultimately bear the athletes' bylines and are published only with their approval. So far, The Players' Tribune has featured more than 1,800 athlete contributors, the bulk of these stories not branded content but instead straightforward pieces. (For branded content stories, the athletes share in the sponsorship revenue, while day-to-day pieces are unpaid.) On the face of it, giving complete control to athletes might result in sanitized stories, glorified press releases intended to boost image. And indeed, sometimes the pieces can run together in a chain of bland, if sincere, recitations of hard-work platitudes. But the pieces can also become surprisingly transcendent, the stories and videos breaking through with raw shocking truths of the sort Jeter had first imagined, tales that would have otherwise likely never been told—in both straightforward pieces as well as branded content. Last September, NBA point guard Isaiah Thomas wrote a series of stories about his surprising trade from the Boston Celtics, how it impacted his young sons and his own life in the wake of the death of his sister, and the resulting tales went viral. A few months later, Kobe Bryant won an Oscar for an animated short based on his retirement letter, "Dear Basketball," which originally ran on the site. And in January, The Players' Tribune debuted a series sponsored by P&G in which the mothers of Olympic athletes detailed how their children overcame struggles, including a story by Olympic freestyle skier Gus Kenworthy's mom, Pip, about her son's challenges as one of the first openly gay athletes in action sports. "It's huge to be able to have this platform to get out our stories and tell people how we feel about certain issues," says Charmeachealle Moore, a linebacker for the Los Angeles Chargers who overcame brain cancer and the death of his father in 2016. "We can let people know we're not just athletes—we're human."

For The Players' Tribune, success in branded content is all due to one guiding principle: authenticity. Instead of gauging success by traditional metrics like numbers of clicks, the site focuses on engagement—the length of time someone spends reading a story. Partly, this stance may owe to necessity. According to ComScore, The Players' Tribune site gets 3.4 million unique views a month, a respectable number but nowhere near the clicks of an entrenched institution like ESPN, which recently attracted 75 million visitors in that same amount of time. But The Players' Tribune model also speaks to the growing importance of brands carving out their own unique spaces in crowded marketplaces and then owning them—a long-tail view of advertising that is increasing in popularity. "The Players' Tribune is putting out content that is really unique and differentiated," says Todd Fischer, a senior VP with sports consulting business GMR Marketing. "It's quality over quantity, and I think that's appealing to brands." In an ongoing series sponsored by Samsung, Richard Sherman, the notoriously press-averse cornerback for the San Francisco 49ers, uploads videos in which he talks about everything from games to his kids to his personal hyperbaric chamber, the entire show taped on his Galaxy S8 phone. The series has been a hit for The Players' Tribune, a perfect pairing of product and athlete, earning over 2 million online views by giving both the athlete and fans a new form of access. "It's very easy to buy audience," says Levick, who claims the site boasts an average engagement time of seven minutes and 45 seconds per piece. "But it's very hard to buy audience that will actually engage with the content. For us, things like sharing and commenting mean we have content that is really resonating, that people care about it and didn't just see it. This is what brands should be paying attention to: How do I insert myself in those authentic narratives that consumers are caring about the most?"

Having already redefined the possibilities of branded content, The Players' Tribune is now moving to its next phase of growth: diversification. In addition to partnering with international superstars like Gerard Piqué and his investment group Kosmos to launch new offices in London and Barcelona, The Players Tribune has recently opened an outpost in Los Angeles to produce shows aimed at television networks and streaming services like Netflix, and even has a feature film in development. For the company, the aim is to diversify its income, moving beyond branded to new fields of revenue and advertising while ensuring it remains true to its core values and tells the authentic stories of athletes. "One of the bigger bets we're making is on video," says David Roter, a former marketing director at Twitter who now works as head of global revenue and partnerships at The Players' Tribune. "I also think experiential marketing is going to have a great future, whether that's a company sponsoring a party or virtual reality experience or people playing video games online. We're constantly running our own studies on branded content to see what pushes the needle. Now brands are relinquishing some of the control they used to want and are coming to the table to let athletes do what they do best: live their lives as social influencers and cultural icons." In the future, The Players' Tribune could even become a new type of social media force by offering tools to help athletes leverage their extensive followings, with everything coming back to players' startup companies, endorsement deals or the media site itself. "I think The Players' Tribune, in and of itself, will become a brand," says Fischer. "It's a unique voice, and there are countless ways it could be leveraged beyond what we've seen so far."

For Jeter, however, the future of his company will always boil down to one guideline: good storytelling. "We've learned it doesn't necessarily take the biggest athlete in the world to pique people's interest," he says, smiling. "It doesn't hurt. But in the end, a story is a story—you bring in people with good content."