Conversation

About #Slack I want to mention that my favourite Free Software projects, #Guix and #Guile, both use mailing lists and (logged) IRC channels

I even linked some old email in those mailing lists in my blog

Also I suggest rreading this document about FLOSS projects using walled gardens comms systems (thank you to @clacke for the link)

https://link.springer.com/chapter/10.1007/978-3-319-57735-7_1