Numerous mail managers exist, and space precludes a comprehensive survey. Only the more comparable ones will be discussed below.
The mail management system most similar to our is ISCREEN []. It allows a keyword and forms-based creation of rules, and offers a simple simulation capability in which a user can pose test messages. In response, the system applies its rules and explains in English what it would have done. Because mail is filtered using a boolean combination of keywords in various fields, ISCREEN can detect that various rules will conflict, and can ask the user for a prioritization. The user can employ organizational expressions (e.g., ``manager''), which the system resolves based on a Prolog-based Corporate Directory database. Our use of the X.500 Directory System Agent offers the same capability based on an emerging international standard.
The TAPESTRY mail system [] incorporates a mail database (as opposed to just a mail file), that is queried by a temporal query language. MAILTALK share this basic underlying model, but rather than have users write temporal queries, the user interface creates the temporal logic expressions through English language desciptions, which are then evaluated over the mail database.
The INFORMATION LENS system [] provides various message types, which can enter into filtering rules (e.g., when a message of type Weekly Sales Report arrives, forward it to ), or can become arguments for other actions (e.g., opening a spreadsheet). This approach takes the first step to integrating mail with other agent-like behavior, but a more fuller integration is possible once it is realized that rule-based mail management is analogous to database monitoring (as shown in TAPESTRY), and that a more general agent architecture can subsume mail management as a special case. It is this latter approach that we are following by embedding the mail manager as an agent in the architecture.