TikTok went dark in the US due to a federal law banning the app, but service was restored by midday Sunday. The ban was enacted due to concerns over potential Chinese surveillance and propaganda. The company had warned that the app would 'go dark' unless the Biden administration made a definitive statement that it wouldn't enforce the ban. The app's long-term prospects are uncertain, with President-elect Trump indicating he will work with TikTok on a solution.