What makes them private? nostr:nevent1qqs2ydu62gx67r0qfcwnhte72862txg5g5kmxrf4nk4wtspme35x6fgpz3mhxue69uhhyetvv9ujuerpd46hxtnfdupzprjr9tg56w246zrrh96h0rcv3qt7lzxf7yvavfk6rgl6eevyhknnqvzqqqqqqyrfyg3y
Only you and the receiver will see all the details
What about the blockchain?