When you share a video link on TikTok, it’ll append a bunch of tracking data to know who opened it and notify you. That’s not really a surprise, but what’s more sneaky is they shorten the “shared” video links into a few unique characters without visible tracking data and parameters in the URL (AFAIK they used to visibly expose tracking data on the URL a few years ago but recently started using a URL shortener).

ie. https://www.tiktok.com/t/ZTRmqkW4N

What seems like an inconspicuous and universal URL for a video actually sends a lot of advertising and tracing data back to TikTok’s servers about your friend/you.