We could have done it with XMPP between Facebook and Google, but that never happened due to some reasons: http://www.disruptivetelephony.com/2015/02/google-fina

We could have done it with XMPP between Facebook and Google, but that never happened due to some reasons: http://www.disruptivetelephony.com/2015/02/google-finally-kills-off-googletalk-and-xmpp-jabber-integration.html http://www.disruptivetelephony.com/2015/02/google-finally-ki... http://aaron-kelley.net/blog/2010/02/a-request-for-federation-s2s-support-on-facebook-chat-xmpp/ http://aaron-kelley.net/blog/2010/02/a-request-for-federatio... AIM also had XMPP support for a bit: https://web.archive.org/web/20110522092331/http://www.aim.com/xmpp https://web.archive.org/web/20110522092331/http://www.aim.co... As did MSN Messenger: http://en.m.wikipedia.org/wiki/XMPP http://en.m.wikipedia.org/wiki/XMPP (in "History" section; sorry, can't dig up link from archive.org ATM )