The server knows the usernames of both parties. The metadata
Discussion
Yes. But it is everyones own freedom to choose a username. So I hope we are not using this freedom to put anything about our real live into this username.
Right now you're talking to me with a picture of you on Nostr. If you were to write in your bio your XMPP username, then any random person on the internet can see it's you. Now the XMPP server sees your life. This means if you want privacy, you should run your own XMPP server.
Can you get some privacy by using others? Yes of course
Totally agree 👍