I recently learned that voting on lemmy is not anonymous. Anyone can get information about who has upvoted and downvoted a post or comment.
In combination with your IP, this is a massive privacy (maybe even physical security) risk. Also, people can target you for your votes.
Sadly, this is something where I would prefer Reddit over Lemmy. Big tech scrapes data from both places anyways, at least Reddit is safe.
Admins have it. And by admin, I assume it is admins of all instances. And anyone can make an instance.
user ip adresses are not federated, only the lemmy.today admin can find your ip
IP addresses are not, and have never been federated. This may shock you, but any admin of any website can see what IP address you’re connecting from if you connect to their site.
