U.S. users worried about TikTok’s future are flocking to an entirely different Chinese social media app: Xiaohongshu, also known by its overseas name, “RedNote.”

The app, founded by Charlwin Mao and Miranda Qu in 2013, surged to the top of Apple’s U.S. app store on Monday. New joiners tagged themselves as #TikTokRefugees, posting guides and videos to their followers on how to set up their own accounts.

Chinese users welcomed their new U.S. brethren, offering to help teach Mandarin Chinese or cracking jokes about espionage.

It’s a surge in overseas popularity for a social media platform that’s already transformed travel and shopping in mainland China, made inroads into Chinese communities in places like Hong Kong, Taiwan and Singapore, and is even changing social media marketing plans in destinations as far afield as the U.K. and New Zealand.

What is Xiaohongshu?

Xiaohongshu is sometimes referred to as China’s version of Instagram. Yet the platform has embraced an array of different functions, including reviews, guides, e-commerce and, well, memes.

The app’s Chinese name translates to “Little Red Book,” which the company claims is from the platform’s origins as a bundle of PDF shopping guides (and not a reference to the famous book of Mao Zedong’s quotations).

Xiaohongshu now has about 300 million monthly active users, primarily young, urban and female–an appealing group for both Chinese and non-Chinese brands. The platform, valued at $20 billion in a 2021 funding round, boasts backing from tech giants like Alibaba and Tencent, and venture capital funds like DST Global and Hongshan Capital.

The platform was on track to earn over $1 billion in profits in 2024, Bloomberg reported late last year, citing unnamed sources.

How is Xiaohongshu transforming travel?

The app in particular prizes personal experience and advice; that’s led many of its users to trust the platform for itineraries on where to sightsee, shop and eat.

“People say: ‘When in doubt, turn to Xiaohongshu,’” Ashley Dudarenok, founder of ChoZan, a digital consulting firm based in Hong Kong and Shenzhen, told Fortune in an interview last year.

Xiaohongshu’s user-contributed advice, seen as more authentic, is changing travel patterns across Asia. Tourist hotspots in Hong Kong, Indonesia, New Zealand and the U.K. now use the platform to attract mainland Chinese tourists and university students.

Xiaohongshu buzz can be lucrative: One Hong Kong-based bakery chain, Bakehouse, told The South China Morning Post that it earned around 90 million Hong Kong dollars ($11.4 million) a year from its sourdough egg tarts, popular on Xiaohongshu.

What’s happening with the TikTok ban?

Unless the Supreme Court intervenes, TikTok, owned by Chinese tech giant ByteDance, will be banned in the U.S. come Jan. 19. U.S. legislation passed last year ordered ByteDance to sell the app, or face a ban.

U.S. officials worried that TikTok sends U.S. user data to China, where it can then be accessed by Chinese officials. They also suggested that China might leverage TikTok’s recommendation algorithm to interfere in the U.S. political system.

ByteDance argues that the divest-or-ban law violates the free speech rights of both TikTok and TikTok users, although Supreme Court justices expressed little support for the Chinese tech company’s arguments.

That means, as of Jan. 19, U.S. TikTok users will have to find an alternative–which, for now, seems to be another Chinese-owned social media platform.

What is Xiaohongshu, the Chinese app also known as RedNote that’s topping the charts ahead of a possible TikTok ban?