When Angelica Oung received a notification that her Xiaohongshu account had been blocked for violating the social media app's code of conduct, her mind started racing.

Aside from her profile picture, the only photo she posted on her account was of her wearing an inflatable polar bear suit and holding a sign that read: "I love nuclear power." Weng, a Taiwanese clean energy activist, wondered what the problem might be.

Is it because her photo looks like someone holding a placard in protest at first glance? Is it because her outfit looks a bit like the white hazmat suits worn by China's coronavirus prevention workers during the pandemic, which became a much-maligned symbol of the lockdown? Or is it because the background is Taiwan’s iconic skyscraper Taipei 101?

Weng never found out. "It's really opaque," she said. “My theory is that Xiaohongshu just got hit with so many new accounts.”

According to Reuters, more than 3 million U.S. users signed up for Xiaohongshu last week. If TikTok is not spun off from Chinese parent company ByteDance, TikTok will be banned in the United States on January 19, with "TikTok refugees" fleeing to the app, also known as RedNote.

On Friday, the U.S. Supreme Court upheld the ruling, rejecting an appeal by TikTok, which has more than 170 million U.S. users, against the ban. Founded in 2013, Shanghai-based Xiaohongshu is an online community focused on shopping and travel advice with more than 300 million users (mostly women). It is reportedly valued at $17 billion.

The surge in new users has forced Xiaohongshu’s moderators to scramble to ensure content on the platform complies with Beijing’s censorship requirements. Unlike TikTok, which is an international subsidiary and has a sister app targeting Chinese users, Xiaohongshu is a purely Chinese operator.

Critics of TikTok argue it poses a threat to national security, as users' data is at risk of being leaked to China. Some lawmakers are also concerned that content on the platform is being manipulated to suit Beijing's interests.

TikTok denies both accusations.

But fearful of losing access to their favorite apps — or perhaps just jumping on a new trend — users ignored lawmakers’ concerns about the Chinese Communist Party and flocked to another Chinese platform.

Like all Chinese social media, Xiaohongshu's content is heavily censored by Beijing's laws, which prohibit content deemed to be against government interests.

In 2022, a leaked internal document revealed how Xiaohongshu censored “emergency events” on its platform, such as discussions about natural disasters and political unrest.

But its existing guidelines are for Chinese-language content. This week, the topic "Red Notes is urgently recruiting English content moderators" went viral on Weibo, and recruitment information for Xiaohongshu English version moderators also appeared on the recruitment website. Chinese officials have reportedly asked the company to ensure that Chinese users cannot see posts by U.S. users.

While Chinese internet users are adept at finding ways around censorship, they are also accustomed to self-censorship and avoiding certain topics that could lead to them being blocked. Over at Little Red Book, they offer some advice for newcomers to the United States.

“Don’t bring up sensitive topics,” advises one lifestyle influencer. “Don’t talk about religion or politics,” said one British user in China, who said he had been posting on the platform for five years.

Los Angeles entrepreneur Christine Lu was also blocked by Xiaohongshu last week. As a test of the app's censorship, she posted images with the Tibetan and Taiwanese flags - both topics considered "sensitive" in China. "As suspected, it is impossible to have a fully self-expressive conversation with Chinese people in China through this app," Lu said on X.

Liu Qiangdong, a former content administrator at Weibo, said: "It is still very difficult for Chinese Internet companies to conduct censorship in English...Censorship mainly relies on the understanding of China's political correctness cultivated in schools and ideological and political courses...You cannot rely solely on translation software."

Xiaohongshu's lack of English language skills means censorship can be "crude and indiscriminate... prioritizing the authorities' requests," Liu said.

Censorship and bans on users could throw cold water on the idea of ​​the app becoming a place for Chinese and American internet users to mingle and share jokes and memes.

"I do think it's a pure benefit that people in geopolitically divided countries can connect with each other, perhaps for good reasons," Ong said.

But eventually there will be a “rude awakening.”

"This is a very interesting test of whether the Chinese government is confident enough to allow this to continue," she said.

Chenchen Zhang, an assistant professor at Durham University, said the current enthusiasm for the unifying power of social media was a "surreal" throwback to the utopian ideals of the internet in the 1990s.