http://tttyx2vwp7ihml3vkhywwcizv6nbwrikpgeciy3qrow7l7muak2pnhad.onion/Summary.html
Applications and users may identify themselves to each other, but the
use of a public network should not automatically reveal to others the
identities of communicating parties. The Traffic Analysis Problem Letters sent through the Post Office are usually in an envelope
marked with the sender's and recipient's addresses.