[Joe_Cool]

Isn't XMPP the base of all major chat services? I used my own client (Psi+) for a while with Facebook chat but since I no longer use Facebook I don't know if that still works. Too bad none of them support federation any longer.

Google Talk/Hangouts still uses XMPP and I use that right now.

[Darmody]

It is the base until it isn't anymore or they just close it in a way that there's no difference between that and any other proprietary chat software.

[Joe_Cool]

That's the problem with completely free code. They are allowed to take it and build proprietary crap with it.