Patent ID: 8190878

Claim:
A computer implemented method of transmitting an electronic message from a first party to a second party who remain anonymous to each other during the transmission, comprising the steps of: (a) transmitting the message from the first party to a service, the message including proxy addresses for the first and second parties; (b) encrypting the address of the first party and a second party; (c) including the encrypted address of the first and the second party in a header of the message in addition to the proxy addresses; (d) decrypting the encrypted address of the second party by the service; (e) forwarding the message to the second party with the first party address encrypted; and (k) sending metadata in the message header between the first and second parties, the metadata includes an indication of whether one or more of a subgroup of less than all recipients have blocked messages from the first party, and whether the second party is in the subgroup that have blocked messages from the first party.