Commenting / Forum / Mail systems
http://plone.org/products/plone-comments
Plone comments
Replaces the standard comment system, moderation, mail notification
etc.
http://plone.org/products/plonemaillist
Plone Maillist
A simple mailing list manager - might be useful to copy code from
http://plone.org/products/easycommenting
Easy commenting
Another replacement for the standard comment system
http://plone.org/products/easycommenting