If a list is open , anyone can send messages to it, not just subscribers. However, only subscribers receive the list's messages. However, moderating a list can be time-consuming and can slow down discussion. On an unmoderated list, all messages sent to the list are automatically sent to all list subscribers. The listserv software can keep old postings in an archive .
Subscribers can send a command to listserv to get former postings.
Archiving the list doesn't require effort from the list owner unless the list is moderated. Most electronic mail systems have some sort of reply command that automatically enters the sender's e-mail address when a response is made to a message. Most systems automatically send replies to the e-mail address that sent the original message. List created at UW-Extension by default sends replies to the list. As a list owner, however, you can decide how the list should handle replies.