I believe you can set it to forward elsewhere. Certainly I see people posting on the other yahoo groups I belong to using email addresses that aren't yahoo. You probably do need to have some form of yahoo account though.
Me, I'm just using them because I don't want to end up with my real email accidentally blacklisted as spam by someone freaking out over newsletter mailings.
If you
really hate yahoo enough that you want absolutely nothing to do with them, visiting the forum frequently will still get you
most news and events. I just like to throw a secret bonus at the newsletter people now and then as thanks for signing up.