Here is the data they are forced to report to the EU:
Logged In X Users 61.8M Logged Out Guests 49.6M Total 111.4M
https://transparency.x.com/en/reports/amars-in-the-eu/amars-in-the-eu-aug-24
“Logged out Guests” is everyone who gets linked to a thread, who was send an video on Twitter and so on. And also take a look at the definition of the logged in users:
EU Active Recipients of the Service - Average between August 1st 2023 - January 31 2024
So you do count as active EU user if you have logged in between August and January with an IP address from the EU. That should even include some tourists.
Yeah, I really don’t understand why people are so confused. From a practical perspective your username is username@instance.tld and that’s it. You’re on some server and can simply follow that guy@mastodon.social and you will see the posts.