Well XMPP is still an exciting protocol - you can pretty much transport anything over it, with federation built in automatically. Basically, if you were using X

Well XMPP is still an exciting protocol - you can pretty much transport anything over it, with federation built in automatically. Basically, if you were using XMPP on anyone's server (even one you stood up) you could talk to any other XMPP user. Google stood up Google Talk and became the largest userbase of XMPP. Facebook also uses XMPP, but they blocked off server 2 server connections. Eventually, Google (recently) replaced their Talk with Hangouts and will be closing off their XMPP service. Anyways, Wave using XMPP isn't very exciting, but the the thing that was exciting about Wave was that it was supposed to be this system that organizations could install and run internally - plus they could share their waves with other organizations that also were running wave servers. Alas, Google stood up one beta server which got overloaded and they never released enough code in a form suitable for anyone to stand up on their own. Apache got a copy of what code was released in 2010 and it's taken 4 years for someone to get it to an easily deployable state.