Well said GeeYouEye... and I have to agree with ChicagoMac as well.
For the folks at Yahoo... Your program isn't that complicated... what's the holdup? Can't you do something to enable the Apple Computer community who want to use Yahoo? Why not make a point of hiring some of the folks from here to do it right? There are some real expert Apple programmers who are regulars here... Just a suggestion Yahoo.
Personally, I use AOL AIM iChat, and it's very stable and has some very interesting features. Now all you have to do is convince the folks you really want to chat with to get an AOL AIM account.