I've found some information about a Tiki mod to help the use of mailman with tiki (or something like that).
Related topic on forums: http://tikiwiki.org/tiki-view_forum_thread.php?topics_offset=1&forumId=6&comments_parentId=12809
Also saw the mod on a plain new tiki 1.9.0 installation, at "Admin > Admin mods" feature (tiki-mods.php). There it says:
Where can I find more information about this mod, howto use it, etc.?
(as far as I understood, it's been made gently by mose )