In 2013, when Chinese Stanford University student Charlwin Mao was considering a name for his startup, he chose Xiaohongshu, which means "little red book."

It references the colors of his prestigious university and his former employer Bain Capital, both bastions of American capitalism.

This week, however, his name choice became the focus of online conspiracy theories that the app is named after a compilation of Chairman Mao Zedong's quotes, which some translate as "Little Red Book."

Xiaohongshu, a popular social media app in China, was not well known abroad until the impending U.S. ban on TikTok led to an unexpected surge in U.S. users. They call it Little Red Book, which does not have an official English name: RedNote.

Last year, U.S. lawmakers passed legislation banning TikTok unless its Chinese owner ByteDance relinquishes control, citing threats to national security. The Supreme Court's decision to uphold the law means TikTok faced a ban in the United States on Sunday, cutting off access to 170 million Americans who have spent billions on the app.

It is ironic that a Chinese social media app with strict content control rules and overseen by Beijing's powerful online censorship agency has become the beneficiary of Washington's ban on another Chinese app, much to the delight of netizens.

But for Mao, it had nothing to do with Chairman Mao, and that was no joke. He operates in a sensitive regulatory environment where regulators will not tolerate any breach of the Great Firewall, a digital divide that separates China's netizens from the outside world.

Xiaohongshu responded to its new popularity in the United States by racing to update its content moderation controls. The company's co-founder and CEO has remained silent, but he has taken pains to avoid being in the spotlight.

Mao Zedong is part of the second generation of Chinese internet entrepreneurs who emerged in the mid-2010s to challenge the dominance of giants such as Baidu, Alibaba and Tencent.

While still at Stanford Business School, he pitched a lifestyle-focused Internet company to investors.

Early funding came from U.S. and Chinese backers Zhen Fund, GSR Ventures and, at the time, GGV Capital. He and co-founder Miranda Qu, a Wuhan native and marketing executive, tested a number of ideas, including creating travel guides for Chinese tourists.

They ultimately settled on a photo-sharing app that focused on lifestyle content. Mao later secured the support of Tencent and Alibaba, a rare achievement for the archrivals. Each invests to prevent the other from acquiring the startup.

Xiaohongshu has more than 300 million active users, who rely on it for restaurant recommendations, travel recommendations and beauty advice, according to data provided to investors. That number will be even higher after this week. It is an important channel for consumer brands to reach shoppers through sponsored posts and influencers.

People close to Mao describe him as a smooth businessman with a mastery of Chinese and American business - skills he honed during his time at Bain Capital.

“There are two types of typical Chinese tech entrepreneurs. One is the nerdy type who wears a T-shirt and sneakers and is shy when speaking in public. The other is the battle-hardened wolf warrior who dictates orders to those around them . ” said one long-time employee.

"Mao Zedong was neither. He was the most stylish of all Chinese tech founders. He spoke with the clarity of a Wall Street elite," they added.

Visitors to Xiaohongshu’s Shanghai headquarters will see a physical representation of its online community. Compared to most austere Chinese corporate offices, it's filled with luscious indoor plants, stylish coffee carts and stages for influencers to shoot videos.

Employees bring dogs and cats into the office every Friday, part of a long-standing tradition championed by Mao Zedong to "create a feeling of home," one employee said. The informal atmosphere is reinforced by the use of company nicknames. Mao adopted the name of the Japanese anime hero Seiya, and the song was named after the historical folk heroine Hua Mulan.

Despite its progressive work environment, Xiaohongshu still has the extreme work culture common among Chinese tech companies. Mao Zedong was known to interview potential employees late at night to demonstrate the commitment he desired. Some point to high employee turnover as evidence of burnout.

This week, employees are working harder than ever. In addition to the challenge of ensuring adequate data center capacity, there are also the sensitivity of hosting the unique exchanges between U.S. and Chinese users.

Many were pleased to see such goodwill ties at a time when geopolitical relations have soured. Those looking to acquire a stake in Xiaohongshu at a valuation of $20 billion have also attracted attention, according to two investors.

Others note, however, that Beijing is unlikely to tolerate Chinese internet users being exposed to more Western content. In the United States, lawmakers who want to ban TikTok may consider Little Red Book as their next target. Given the strained relations between the two countries, Little Red Book's moment in global popularity may be short-lived.

eleanor.olcott@ft.com, zijing.wu@ft.com

Additional reporting by Wenjie Ding and Nian Liu in Beijing