@jonkulp Remember legacy instant messaging ( AOL's #AIM, Microsoft's MSN Messenger, Mirabilis's #ICQ, Yahoo's Y!Messenger, and so on)? #Jabber / #XMPP starts as a #federated and extensible version of those IM systems, but can also do more. (Google Talk used to be an XMPP service before it became Hangouts.) @jim @cmhobbs