Google GTalk clients (web, android, windows) have great ability to suck conversation history from server, even though conversations were done an another jabber client.
- What jabber (XMPP) functionality (XEP) is used for that or is it some custom thing?
- Why no other XMPP client (non Google) has this ability?
P.S. It is programming question, because I am asking about specific XMPP functionality.
It is possible that this is done using message archiving. See XEP-0136: http://xmpp.org/extensions/xep-0136.html
(And with regard to the other answer, this is supported by ejabberd: http://www.ejabberd.im/mod_archive)