Just yesterday there was a great post by Michael Robertson, advocating IM interoperability, on http://www.michaelrobertson.com/archive.php?minute_id=192. I commented at the time that since Google promised to open Google Talk, and Yahoo said they'd be more open than Google, this couldn't but ripple through to complete interoperability: http://www.gizmojournal.net/2005/10/citizens_revolt_to_abolish_im.html