Voila! I give you XMPP + threading: http://xmpp.org/extensions/xep-0201.html http://xmpp.org/extensions/xep-0201.html (last updated Feb. of last year) Wave is

Voila! I give you XMPP + threading: http://xmpp.org/extensions/xep-0201.html http://xmpp.org/extensions/xep-0201.html (last updated Feb. of last year) Wave is XMPP, with additional Google extensions for a variety of collaboration features. That is possible because the first letter in XMPP doesn't stand for "XML", it's the (annoying but common) "eXtensible", suggesting that domain-specific additions are not only accepted, they are encouraged.