Telegram group already active
Discourse working already (duh)
Liminal Village website up already.
Hackalong.io could use a front page over this Discourse however.
Interspace.chat is up for synchronous video calls 
(or share a Jitsi)
Zulip server & invite link (getting work done chat)
GitHub - Primary
GitLab - Alternative
Open Collective - accounting for things
Currently no Twitter, but perhaps should be Mastadon or Libpub instance etc
What do we think?