I opened up Yahoo! Groups and I see that it has got a new look.
I really hate the choice of colors - light blue really doesn't cut it for me - I can't figure out how to change that in the settings. The 'Management' section for moderators is really useful. If it was already there in the old look, I haven't noticed it before. The vitality alerts are interesting and the GMail-style snippets look of the groups is a nice touch.
Now, if only they did something to browse by threads like Google Groups conversations, that would be great.
Update: I totally fail to understand one thing - why is the new and redesigned (emphasis on new) design of Yahoo! Groups not using XHTML?! They are still using HTML 4.0. Even MSN Search is XHTML Strict compliant!