Not quite sure what kind of privacy you need, but matrix is reasonably easy to self host, and allows you to federate if you want.

Also has plenty of clients.

If you want low tech, hosting IRC is easy too.

You know, I think it could have merit to have politics more transparent. Being able to see which person / lobbyist proposed and got which exact changes in, that would be very enlightening.

Also getting the discussions that happen behind the scenes out in the open… I would like that. Never mind the flame wars.

They are currently adding calendar support, which is the most feature for me. We are looking for work it’s integration.

Relevant cargo Plugin https://github.com/Gankra/cargo-mommy