FWIW, I am now using Pidgin, which allows you to hook into all the different chat networks. Time will tell if it's any good...
"Pay no attention to what the critics say. No statue has ever been erected to a critic."
Pidgin on the pc and Adium on the mac for me. No problems at all
I've not used it so can't comment, but in Firefox it lists Yoono as a recommended 'add-on' for bringing all the social networking/messaging things under one browser extension or separate desktop app.
For a moment there I felt like I had an idea what any of that meant.
Well, Pidgin seems to be working out fine. Nice enough interface and - unlike MSN - it doesn't feel like my laptop is about to combust at any moment when it is running.
Pidgin, the universal chat client