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. Unless everyone on the list is likely to have the same specific problem, the answer won't be of interest to everyone. Setting replies to go to the list will increase traffic on the list, which is good if your goal is to generate discussion. A disadvantage of having replies go to the sender instead of to the list is that sometimes the reply can be of benefit to everyone.