The identifier to send someone a message, or to identify where a message came from. See RFC 822.
Addresses can point to mailboxes or aliases.
Depending on the program, actions might include transferring messages, replying with pre-written responses, deleting messages, etc. Junk e-mail or newsgroup posts, usually sent in bulk. The eMailman character is a service mark of Andrew Starr. Other marks belong to their respective owners, either Andrew Starr, or others.