Six months ago, Snapchat founder Evan Spiegel made a trip to China, where he met Tang Yan, who started a Chinese social network called Momo that now has 60 million monthly active users.

The two commiserated over being young upstarts—albeit ones with multibillion-dollar valuations backed by some of the world’s top investors—facing much larger competitors. For Snapchat, that competitor is Facebook and its new messaging system; for Momo, it’s WeChat, the Tencent social network in China with 440 million active users.

Each heard similarities in how the other spoke about the competition. “We both agreed that the bigger company is not good enough,” Tang, 35, told Fortune recently in Momo’s offices in northeast Beijing, located within a gleaming new complex designed by Zaha Hadid. “There’s still space.”

More than enough space, it turns out. Momo, a location-based social network allowing users to find new friends nearby, has become one of the most popular apps in China. The massive growth of cities in the past few years helped: new migrants want new friends. But so has a more liberal Chinese attitude toward dating and sex. And the rise of the smartphone has made social apps like Momo indispensable to finding new mates—so much that Momo is planning an IPO that values the company at $3 billion, according to a consultant and Chinese press reports. Just as everyone on Wall Street got to know Alibaba, they might soon be pitching Momo. (The name has no meaning—the founders just wanted something easy to say— but it includes part of the Chinese word for “stranger.”)

The chat with Spiegel gave Tang a fresh perspective on his company. Momo had gained a reputation for being “a magical tool to get laid,” as Chinese-American comedian Mike Sui put it, as well as “hormone-filled,” China’s state media said. News broke earlier this year that the government’s pornography regulator had warned Momo about some profiles on its network. (Momo has closed 9 million profiles linked to prostitution, spamming and lewdness.)

Snapchat, too, gained a tawdry reputation of its own in the U.S., which didn’t do much to slow its growth. Instead of avoiding the subject like the company’s public relations aide when I asked her about it, Tang embraces it, comparing Momo to a “combination of Snapchat and Tinder” and pointing out that, yes, some people use it to hook up, but many others log on in hopes of finding friends to share a taxi, get lunch together in the office park, or talk with about everyday topics like parenting in Beijing.

Tang has the puffy eyes of someone who prefers to work at 1 or 2 in the morning, a time of day he admits to getting his important work done. On a recent afternoon he’s wearing jeans, a T-shirt, and special-edition Nike sneakers. He has the aura of someone new to it all and excited to be here. His office chair still has the plastic price tag loop on it and in a recent GQ China profile, he says Yuri Milner, the billionaire Russian VC, shipped him a special whiskey. “I don’t know the brand, but Yuri said it was fabulously good,” Tang said.

After growing up in the central province of Hunan, Tang spent eight years at the news site of 163.com, one of China’s top Internet portals, eventually running it, before getting the idea for Momo when location apps like Foursquare were gaining popularity. At the time, Chinese apps didn’t offer a lot of options to find new friends—existing networks like QQ, Ren Ren, and WeChat were premised around improving relationships you already had. Tencent’s WeChat, which actually launched a geo-location service just one day before Momo came online in August 2011, hasn’t overtaken Momo in part because the WeChat is about the privacy of your own social network.

Momo’s success, says co-founder Wang Li, who chose Wanderlust as his English name, is explained by a couple broad themes. First, the urbanization rate in China sped up by almost 50% the year Momo started its service, which bolstered an app selling itself as a way to meet strangers. Second, he says, the Chinese just aren’t very good at meeting strangers—in the countryside’s small villages, everyone knows everyone—so when migrants come from the countryside to the city, they don’t have the right skills. “When they come to new place, they are totally in a strange world,” he says. Wang recommends watching the 2011 documentary Last Train Home to understand how urbanization in China is upending the country’s mores.

The networks reflects modern day Chinese society. When it comes to meeting strangers, men are more aggressive than women—Momo users are 66% percent men to 33% women—but women hold the attention. A female Chinese friend of mine was embarrassed when I asked if she used it. Of course not, she said. She has a boyfriend. But many of her Beijing female friends use it to find dates and flirt.

As a rough estimate, Momo says about 5% of the 900 million messages a month sent across its network are about ‘hooking up.’ But the more than 60% of messages that are traded between two people might be leading to the same discussion. Wang says, “We don’t have charges, whether that’s a good thing or bad thing, because it’s free social network.” He points out the percentage of successful one-nights stands is quite low because it requires high social skills and luck. In China, “it’s not easy to get a real one night stand,” he says.

After Tang made a comparison to Tinder and Snapchat, I asked Wang what company Momo wanted to be like. He said he saw The Social Network—David Fincher’s drama about Facebook’s early years—and came away impressed. “The founder of Facebook had problems with his personality—he was shy, initially angry,” Wang said. He saw the same tendencies around him. “For the young Chinese generation, and Chinese in general, they are not very open-minded and don’t have an outgoing personality.

“But technology makes things change,” he says.

Venture capitalists often ask Tang what he expects the company to look like in three years. He laughs when I ask him the same question. Momo brings in cash from some paid add-on features, he says, but it’s just now exploring new business models, such as running ads from close-by restaurants and small businesses. The company recently opened a subsidiary in San Francisco but isn’t sure if it will launch its service in the U.S. An IPO remains a while away.

Today, every young person in China knows of Momo—and Tang thinks that’s more than enough to drive the company for now.