An interesting article about Jabber/XMPP MUCs, a.k.a "groupchats", a.k.a "rooms", a.k.a. "channels":

“In the software development field, and much in the libre software, group’s discussions are really common, mostly with IRC (Internet Relay chat). This venerable protocol do what we ask it and XMPP is strongly inspired by it. Let’s see that closely.

Group’s discussions used nowadays are called MUC (Multi-User Chat) and are defined by XEP-0045. This one standardizes and extends the first solution called Groupchat. As all that comes from IRC, I’ll explain as they come the major differences between them.

[...]”

http://www.goffi.org/post/2015/08/26/Let-s-talk-XMPP-episode-4-group-conversations 

Via Planet Jabber.