This is the cycle of the Web. Stage One: somebody creates something that's good, and people like it because it's useful and it works pretty well. Stage Two: a big company buys it. Stage Three: the idiot web designers are let loose and redesign it, thereby making it dramatically worse. Stage Four: users leave in droves.
Hotmail is a classic case of a service that was good when it started but, after Microsoft bought it, was made markedly worse by repeated redesigns, to the point where it would now be overly kind to describe it as rubbish.
Now it looks as though Yahoo! has applied its own design idiots to Yahoo Groups, with entirely predictable results.
There's already a petition with more than 23,000 signatures that pleads: PLEASE CHANGE the New Yahoo Group Look back to the Original...
Still, I do admit to finding it pretty funny that, just as the geeks are belatedly "rediscovering" The UnGoogle (Yes, Yahoo!), the wheels could be starting to fall off.