In a newsgroup, the message you write is not directed to someone's mailbox; instead, it is posted all over the world to be read by anyone who chooses to do so. Note that this requires that the recipient actively seek out the message by reading the newsgroup(s) to which you post: Nothing will show up in his mailbox.
List servers maintain distribution lists and handle the job of sending copies of email to those who have asked to be included in specific lists by "subscribing." When someone sends email to the BANJO-L list, a copy of his message will miraculously appear in the mailbox of everyone who is subscribed to this particular list, including--at his option--the sender's. In many ways, therefore, a "list" is like a special delivery newsgroup that can only be read by subscription.
There are numerous options and settings that can be made for such lists. For example, on BANJO-L and many other lists, only subscribers can post messages. On other lists, anyone can post to the list; of course --unless he's a subscriber--he will never see his own message.
Another setting is how the list will handle "Reply-to" instructions. BANJO-L is currently set to mark all messages as "Reply-to-List," i.e., if you choose to reply to a message, by default your reply will be sent to all the current subscribers, not just the message's author. This, of course, makes for some interesting moments, when you decide to reply to person "X" to complain about what a jerk person "Y" is, but forget that your reply is going to be sent to hundreds of people, including person "Y." You will usually realize that you have done this within nanoseconds of having sent the message, of course.
These settings and others are handled by the List Owner, who, in the case of BANJO-L, is Marc Perdue, and to whom any questions about BANJO-L should be directed. Instructions for subscribing to BANJO-L are provided on this site.
There are some basic, common sense guidelines for posting to this (or any other) list; if you are new to the idea of posting email to hundreds of people, please read these suggestions.