Hi all, I'm pretty new to the fediverse and have tried learning about the way it works. I have tried finding some information in vain, so I have ended up mostly reasoning about it by drawing parallels with other non federated systems but I feel it's not accurate.

I am trying to understand three things:

1. What information does the instance(s) have on their users?
2. What information can users get on other users?
3. What information can the infrastructure providers get on users of the fediverse?

To answer (1), I am guessing the admins of the instances have access to the typical metadata relating to the device from which a user accesses (IP address, device info, app/browser).

Regarding (2), it's not as clear. As of yet, it seems it is only possible to look at posts and comments and creation date. It doesn't seem possible to get a list of subscribed communities nor email address used for registration (when applicable).

Now I wonder if the instances do have all lists of subscribed communities? I'm guessing yes. What about private messages, are they end to end encrypted and inaccessible to the fediverse?

And finally, what access do the internet infrastructure providers have access to? All the same information as the instance admins/mods? More? Less?

Thank you for helping me weed through this new environment and learn about the fediverse.

Also, if you have some best practices on how to mindfully navigate in the fediverse with privacy in mind, please share, I would be grateful.