Gtalk and Facebook messenger both used XMPP. XMPP is federated so it allowed many people to easily communicate. Even MSN messenger got on board: http://msdn.mi

Gtalk and Facebook messenger both used XMPP. XMPP is federated so it allowed many people to easily communicate. Even MSN messenger got on board: http://msdn.microsoft.com/en-us/library/live/hh826554.aspx http://msdn.microsoft.com/en-us/library/live/hh826554.aspx AIM also has limited XMPP support (although that is just from a quick Google search, can't figure out if that is still the case). Either way more and more clients and chat protocols were beginning to converge onto a single standard, that allowed people to easily communicate across different "domains". That is now going away.