Different levels, yes!
All over IP, i.e., the Internet, yes too!
No contradiction. ;)
Discussion
What about Email?
Email, SMTP/IMAP/pop protocols, tuns over TCP IP...
Still internet, but interesting idea. You could point out your mailbox in your imaginary nostr client and it could be used as the channel to exchange notes.
The mailbox would be a sort of relay, they are quite dump actually.
I was thinking your Nostr client could strip out your IP from the email header and then you could send it to a mailserver-relay and they'd know it isn't spam because you signed it with your not-blacklisted key.
Or something.
Like, instead of masking/borrowing IP addresses, create a special Nostr communical path that you can use anonymously.
Was just thinking that we have this super-anon protocol running over IP addresses and it's like...
Why tho?
Emails are actually not that good at privacy, e.g., hiding IP address. Traditionally clients insert your prv IP address in the email header. Luckily email providers strip them down, mostly, but that depends on the email provider.
I was thinking e-mail because I was using it before Internet became popularized. It predates the Internet and can working without it.