Google keep the chat client open but have an option to hold back all but the most important packets on the server side and then batch send them after a set period of time. This is something along the lines of http://xmpp.org/extensions/xep-0273.html
The current nokia version of buddycloud (http://mobile.buddycloud.com) will run continuously for for about 18 hours. The android version with batch sending of packets even longer.
And if you worry about XMPP's verbosity, just add the DEFLATE option to your TLS socket. That drops the size down to about 10% of the original.
Polling is worse.
Google keep the chat client open but have an option to hold back all but the most important packets on the server side and then batch send them after a set period of time. This is something along the lines of http://xmpp.org/extensions/xep-0273.html
The current nokia version of buddycloud (http://mobile.buddycloud.com) will run continuously for for about 18 hours. The android version with batch sending of packets even longer.
And if you worry about XMPP's verbosity, just add the DEFLATE option to your TLS socket. That drops the size down to about 10% of the original.