@ amogorkon: It would be another protocol. A simple, high level one (layered on top of the Jabber protocol), but nontheless a protocol. But I assumed you\'d want to pipe PS traffic through a shared Jabber account, but instead you seem to propose using individual ones.
That, however, would require everyone to have a Jabber account and be willing to tell you about it. I do have one, but I am most definitely not willing to share it with almost everyone in PS.
This means that either each PS account would need an automatically created Jabber account, or the entire communication in /group, /tell or /guild would be available only to those who have one and share it with you, thereby effectively locking me (and others with similar mindset) out of some parts of PS communications, which clearly can\'t be the intent.
Also, you propose to have the conventional system in place in case the Jabber network isn\'t reachable (or, by extension, if the other player didn\'t supply a Jabber account). Now this obviously doubles the burden on the devs instead of lessening it: they will not only need to maintain and troubleshoot the conventional system, but also the interface to the Jabber network. So this clearly is not saving work.
The only thing that your system could realistically provide is a separate tab. This has been done for IRC already. However, this tab would be the exact same as your normal Jabber client, and have no connection to PS save being integrated into it\'s GUI. This I wouldn\'t mind, but it\'s definitely something that I wouldn\'t want the devs to waste their time on.
Yes, fullscreen players have a problem ATM, because of the PS crashing when tasked away bug. However, this bug will eventually vanish. Also, I think that a Jabber client is a very simple application that doesn\'t put much of a processsing burden on the user\'s system, so it won\'t really be noticable AFAICS. Yes, the missed gameplay does apply, but then again, imagine your Jabber talk inside the chat window... it\'d essentially drown out the IC conversations. The solution would be to only have Jabber chat in the JAbber tab, which would obviously make for the same problem as tasking PS away, save the temporary crash issue.
All in all I still fail to see real benefits.