I built an email-powered social network called Uhuro (https://uhuro.com/). I guess it could also be used as a social listserve platform.

Email addresses work like APIs. For instance you can send emails to [email protected] to join the social network or [email protected] to quit. Other email API addresses include:

- [email protected] = invites friends and family to join

- [email protected] = Replies with the instructions

- [email protected] / unfollow@ = Follows or unfollows CC'ed users

- [email protected] = Replies with all users following you

- [email protected] = Sends your email message to all of your followers.

Here's more information on how it works - https://uhuro.com/how.html