Live Chat

Real Time Group Discussion, aka Group Chat

• for one-to-one see Instant Messaging
  • sometimes Instant Messaging systems support group "room" - see Group Messaging

options

• slack.com
• Matrix.org
• Mattermost
• MicrosoftTeams
• NextCloud/talk

IRC is the Open Standards player. Most people seem to rely on freenode for hosting IRC.

One challenge in terms of using this as Collaboration Ware is that these don't give Threaded Discussion, which can result in a mess, esp as number of concurrent users increases (beyond 2).

For web-based, see WebChat.

Audio: Mum Ble http://mumble.sourceforge.net/

I wonder whether there could be a P2P version?

Do you want a transcript?