Along these lines, someone else mentioned that Tiktok embeds direct tracking into URLs already.

Twitter recently started adding a 't=' param to their share links [0] as well, and I can only guess that it's some kind of similar tracking scheme. From watching browser traffic it appears to be generated when you click the share button, but I might be wrong about that.

[0] https://twitter.com/NanoRaptor/status/1548301612246249474?s=... - the first thing in my feed. Link works fine without any of the query params, of course.