MAIL8 is an electronic mail package for the GCOS8 system. It supports Internet-style addressing, as well as many other common features of Internet mail (e.g. MIME encoding).
MAIL8 was designed with a simple philosophy: 100% reliability. MAIL8 systems don't let E-mail messages "disappear"; they give positive confirmation of receipt, or they give you a diagnostic message explaining why a message couldn't be delivered.
[Note: Since other E-mail systems don't have this reliability philosophy, confirmation cannot be provided if a message has to pass through other mailers before reaching its final destination.]