The four papers contained in this document provide: (1) a survey of computer based mail and conference systems; (2) an evaluation of systems for both individually addressed mail and group addressing through conferences and distribution lists; (3) a discussion of various methods of structuring the text data in existing systems; and (4) a description of the networks of interconnected systems: ARPANET, CSNET, BITNET, USENET, JNT-MAIL, EURNET, and MAILNET. Specific topics such as electronic mail, electronic publishing, structuring facilities, subconferences, keywords, simultaneous conferences, and mail networks are also described, and the differences between computer conferencing and electronic mail are explained and illustrated. A detailed description of the COM/PORTACOM computer conference system, which provides both computer mail and conference system services, is included, and the command structure of menus and listed commands used by the system are illustrated. A short summary of a report on experience with COM usage is included, together with a cost estimate (in Swedish kroner) for system utilization. An outline of the functions and implementations of COM/PORTACOM facilities is provided to explain the use of the system in detail. (JB)