Duolingo shares have jumped this week, as the number of Americans learning Mandarin on the app has soared 216%. That's as China's RedNote is now the most downloaded free app on Apple's App Store ahead of the TikTok ban.

As self-described " TikTok refugees" pour onto the Chinese social media app RedNote, also known as Xiaohongshu, some foreign netizens are already running up against the country's extensive censorship apparatus. Newsweek reached out to Xiaohongshu with a request for comment via a general contact email address.