Here's a link:
https://www.boredpanda.com/tik-tok-reverse-engineered-data-information-collecting/?utm_source=google&utm_medium=organic&utm_campaign=organicThings it seems it does:
1) Ping your GPS periodically
2) keep track of all the cookies on your web browsers
3) Keep track of all the hardware id's your user uses to access the site
4) Keeps track of all the apps you install and uninstall
5) Keeps track of all networks stuff it can get, including IP address, Wi-Fi router MAC, device MAC, etc
6) Tries hard to hide all of the data it is collecting and sending to their servers in chi-nah
7) Measures your user activity, based on what you swipe and what you don't.
In all, it is public spyware in the guise of a video streaming service. Imagine if Twitter, Facebook and Google were all owned by the Chinese government. Because it collects more information about you than all three of these combined.
What good does that do? All speculation, but if I was an evil dictator with this type of information:
1) It helps them with their foreign policy around U.S. How do we get them to panic and crush their economy? I know... MASKS!
2) It helps them identify government workers, and who they work for. If you have an App installed that logs into a US government intranet or sends email through a US government email server, they will know, and they can target you for better information.
3) It helps them identify targets for corporate espionage. Same concept as #2, but if you are logging into a Lockheed intranet on your phone, guess who just became interesting to the Tik Tok guys?
4) It helps them identify where high-value targets physically go, shop, log into weakly protected or unsecured Wi-Fi so that for the really high value targets, you can sit and sniff.
There is a reason why US government employees cannot have it on their phone. And it's not due to trade war stuff.
"Laws that forbid the carrying of arms … disarm only those who are neither inclined nor determined to commit crimes… . Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than to prevent homicides, for an unarmed man may be attacked with greater confidence than an armed man.”
--Thomas Jefferson