What is Mailing Group - Listserv?
WordPress mailing group is a plugin that allows you to run a free Listserv or email group just like Google Groups or Yahoo Groups right from your WordPress dashboard. Group members can use their favorite email clients to interact with the group, no need to login to dashboard. They can send plain/text or HTML emails with attachments. The plugin offers various email sending options and also allows to add an SMTP server for outgoing emails.
There are several options to add users to groups like importing existing wordpress users to a mailing group easily with one click or a form on the website where users can submit their details and sign up for a mailing list. This is NOT a one-way Announcement list where only YOU can email everyone else. Its the best two-way group email communication plugin where any email sent to the main group email gets forwarded to the all group members. Members can unsubscribe from the list anytime by the unsubscribe link provided in group email footer. The group email footer is fully customize-able.
Mailing Group - Listserv Screenshots
Mailing Group - Listserv information
Comments and Reviews
Said about Mailing Group - Listserv as an alternative
Its a really nice Google groups and Yahoo groups alternative listserv mailing list plugin.