I use a Matrix channel (which is bridged to an IRC channel) for this purpose. I host computing book club meetups in the weekends. While the meetup main page and

I use a Matrix channel (which is bridged to an IRC channel) for this purpose. I host computing book club meetups in the weekends. While the meetup main page and notes are hosted on a website, I have Matrix and IRC channels where the meetup participants can hang out together, follow schedule updates, make friends, etc. All our communication is in text format, so these open protocols and platforms serve our needs pretty well. The group members have the freedom to use any free and open source client or one of the popular web interfaces to join the channel and talk to each other. Should something go wrong with the Matrix or IRC network (say, the network becomes user-hostile for some reason), it is a simple matter of moving the channel to another benign network. The group members only need to point their clients to the new address. In fact, such a thing did happen once in 2021 when Freenode went through major staff changes due to disagreements with how the network was being run. All channel operators (myself included) moved their channels to Libera in a matter of days. It took me only about 5 minutes to complete the migration and hand out the new channel address to the channel members.