This section contains some miscellaneous settings for your mailing list.
This variable presents a set of checkboxes which control the defaults for some of the member options. Conceal the member's address specifies whether or not the address is displayed in the list roster. Acknowledge the member's posting controls whether or not Mailman sends an acknowledgement to a member when they post a message to the list. Do not send a copy of a member's own post specifies whether a member posting to the list will get a copy of their own posting. Filter out duplicate messages to list members (if possible) specifies whether members who are explicitly listed as a recipient of a message (e.g. via the Cc: header) will also get a copy from Mailman.
Of course, members can always override these defaults by making changes on their membership options page.
-requestaddress for the list. Setting this to Yes helps prevent such things as unsubscribe messages getting erroneously posted to the list.
If a message seems to contain administrivia, it is held for moderator approval.
example.compart of the posting address
It's generally not a good idea to change this value, since its default value is specified when the mailing list is created. Changing this to an incorrect value could make it difficult to contact your mailing list. Also note that the url used to visit the list's pages is not configurable through the web interface. This is because if you messed it up, you'd have to have the site administrator fix it.
However, not all mail readers are standards compliant yet, and if you have a large number of members who are using non-compliant mail readers, they may be annoyed at these headers. You should first try to educate your members as to why these headers exist, and how to hide them in their mail clients. As a last resort you can disable these headers, but this is not recommended.