Configure Mailman as an announce-only Newsletter list
10) At the next section, Privacy options, select “No” to the question “Advertise this list when people ask what lists are on this machine?“. Towards the end of the questions, select “List admin only” to the question “Who can view subscription list?”
11) Still in Privacy options, go to “Sender filters” and select “Yes” to the question “By default, should new list member postings be moderated?” and select “Discard” as the “Action to take when a moderated member posts to the list.” Next add a nice rejection notice text to the text box, such as “this is an announcement list; to reach me please email at [email protected] or visit my contact page at …”
Still at “Sender filters” add a non-member address that will always be moderated (not discarded); this is the address you are going to use to post your Newsletter to the list. Since all member addresses will be discarded by default, you need a non-member address to post to the list — and this one not approved by default (in case someone impersonates you), but always moderated.
12) Finally, to let the visitors of your site subscribe or unsubscribe easily, you can have on your site a form that would send to yourlistname-request@yourdomain these commands (without brackets around the email address):
subscribe address=<ADDRESS> or, unsubscribe address=<ADDRESS>
Remember to include a link to your unsubscribe page in each issue of your newsletter. Enjoy!