Try installing this add-on: Yahoo Mail Notifier

Looks like it worked, but why did they move notifications down to the bottom of the screen instead of up where the mail icon is in the toolbar? I prefer it up there; it's more noticeable up there.

I can't answer that one I'm afraid. You could try emailing the developer. You'll find the email addy on the same page you downloaded the add-on from on the right hand side where it says "Need help with this add-on".

Oh, and could you please click the "Solved" button which will take this thread out of the loop and allow other contributors to concentrate on helping other users.

Thanks.