: Built-in archiving, automatic bounce processing, content filtering, and integrated spam filters.

“Mailman has dramatically made my inbox more sane and manageable.” Mailman HQ

This is free, open-source software used by organizations to manage electronic mailing lists and e-newsletters. It is written in Python and distributed under the GNU General Public License.

: Reviewers generally consider it one of the best mailing list managers available, though some "old school" versions were criticized for mailing out passwords in plaintext by default. 2. MailmanHQ (Gmail Productivity Plugin)