Emerson Spartz calls himself an aggregator, but he acts more like a day trader. Illustration by Oliver Munday

One afternoon in June, Emerson Spartz, an Internet-media entrepreneur in Chicago, left his office and walked several blocks to the Museum of Contemporary Art, where he was scheduled to speak at an event called the Millennial Impact Conference. He and other participants had been asked to discuss ways that young people using technology can “build movements to create change.” This is not Spartz’s specialty. “I basically have only one speech,” he told me. “It’s about how to make things go viral. I have personal preferences about how I would want those principles to be applied, but in practice they can be used for pretty much anything.”

Spartz is twenty-seven and has been successfully launching Web sites for more than half his life. In Chicago’s small startup subculture, he is an envied figure. On his way to the conference, he ran into Jimmy Odom, a thirty-three-year-old businessman with dreadlocks. Odom described Spartz to me as “inspiring” and “legitimately awesome.”

“Why won’t you accept my friend request?” Odom asked him.

Spartz grinned apologetically and said, “Facebook puts a cap on how many friends you can have”—five thousand—“and I’m at the limit.”

In 1999, when Spartz was twelve, he built MuggleNet, which became the most popular Harry Potter fan site in the world. He appeared on CNN and Fox News, and J. K. Rowling invited him to her estate in Scotland. He eventually lost interest in Rowling—although he bought “The Casual Vacancy,” her recent novel for adults, he said he hadn’t yet read it—but he remained fixated on commanding young people’s attention online. “As I became less motivated by my passion for the books, I got obsessed with the entrepreneurial side of it, the game of maximizing patterns and seeing how big my reach could get,” he said.

Web development is a low-overhead enterprise, especially when you live with your parents. MuggleNet made hundreds of thousands of dollars through advertising, and Spartz funnelled his earnings into a new company: Spartz, Inc. His first employee was his younger brother Dylan, who designed the site; during college, at Notre Dame, Emerson started working with Gaby Montero, then his girlfriend and now his wife. After graduation, they started building rudimentary Web sites, sometimes as many as one a month: GivesMeHope (“ ‘Chicken Soup for the Soul’—the twenty-first-century, Twitter-style version”); Memestache (“All the Funny Memes”); OMG Facts (“The World’s #1 Fact Source”). Many of the sites fizzled out; others gained a following. When Internet culture developed a fascination with “fails”—news bloopers, errant autocorrects—Spartz created a site where users could post funny mistakes from Facebook (Unfriendable), a site featuring gaffes from television (As Failed On TV), and one about garbled text messages (SmartphOWNED). When the data indicated that optimism was attracting more visitors than Schadenfreude, Spartz let his “fail” sites languish and focussed on promoting GivesMeHope, a repository for anonymous, uplifting anecdotes.

Last year, Spartz, Inc., raised eight million dollars in venture-capital funding and made several million more in advertising revenue. As new-media companies like BuzzFeed and Upworthy become established brands, Spartz hopes to disrupt the disrupters. He employs three dozen people full time, in addition to several freelancers. The company operates thirty sites, which have no unifying aesthetic. Their home pages, which can be chaotic and full of old links, don’t always feature a Spartz logo; traffic is generated almost entirely through Facebook, so brand recognition is relatively unimportant. Most of the company’s innovations concern not the content itself but how it is promoted and packaged: placing unusually large share buttons at the top and the bottom of posts; experimenting with which headlines and photographs would be more seductive; devising strategies for making posts show up prominently in Facebook’s news feed. “I keep hearing people around town talking about this young man as a Steve Jobs kind of guy,” Gary Holdren, one of Spartz’s chief investors, told me. “I think his stuff is indicative of where digital media is headed.”

At the museum, Spartz waited backstage while Jake Brewer—a manager at Change.org, a platform for petitions—delivered a speech about online organizing. Brewer, who is thirty-four, warned that online activists needed to be more strategic. “The Internet has created a huge megaphone,” he said. “That’s great, but it often creates so much noise that the people on the receiving end can’t hear anything.”

Spartz took the stage, wearing a cordless microphone. People who achieve success at an early age often retain a childlike aspect into adulthood, and Spartz has the saucer eyes and cuspidated chin of a cartoon fawn. His hair style (a tidy mop top) and clothing preferences (heathered T-shirt, dark jeans, black sneakers) have not changed much since his tween years. A screen in front of a velvet curtain displayed, in jaunty type, “Hi! I’m Emerson Spartz. I want to change the world.”

When he was growing up, Spartz said, his parents made him read “four short biographies of successful people every single day. Imagine for a second what happens to your brain when you’re twelve and this is how you’re spending your time.” He used his hands to pantomime his mind being blown. “I realized that influence was inextricably linked to impact—the more influence you had, the more impact you could create. . . . The ability to make things go viral felt like the closest that we could get to having a human superpower.”

He offered practical tips: “Facebook should be eighty per cent of your effort, if you’re focussed on social media”; “Try to change every comma to a period”; “Use lists whenever possible. Lists just hijack the brain’s neural circuitry.” Behind me, two women in their fifties took notes on legal pads. In summary, Spartz said, “The more awesome you are, the more emotion you create, the more viral it is.” One of the women whispered, “Really impressive.”

Spartz left the stage and walked to his office, a mile away, without stopping to see the Isa Genzken retrospective upstairs. “People have hoity-toity reasons for preferring one kind of entertainment to another,” he said later. “To me, it doesn’t matter whether you’re looking at cat photos that inspire you or so-called ‘high art’ that inspires you.”

I had met Spartz a few weeks earlier, at a dinner during a tech-industry conference in Manhattan. When I asked him what he did for a living, he replied, “I’m passionate about virality.” I must have looked confused, because he said, “Let me bring that down from the thirty-thousand-foot level.” The appetizer course had not yet arrived. He checked the time on his cell phone and cleared his throat. “Every day, when I was a kid, my parents made me read four short biographies of very successful people,” he began.

On this occasion, I was the only person listening to his speech, but he spoke in a distant and deliberate tone, using studied pauses and facial expressions, as if I were a video camera’s lens. When he got to the part about virality being a superpower—“I realized that if you could make ideas go viral, you could tip elections, start movements, revolutionize industries”—I asked whether that was really true.

“Can you rephrase your question in a more concrete way?” he said.

I mentioned “Kony 2012,” a thirty-minute film about the Ugandan militia leader Joseph Kony. It has been viewed on YouTube more than a hundred million times, but it did not achieve its ultimate goal: Kony remains at large, as does his militia, the Lord’s Resistance Army.