Rated 5 out of 5 stars

Simple and effective (even without all the options with which it comes folded) this add-on is a must have for any Yahoo mail user.

The ability to glance discreetly at an icon to see if you've got incoming email(s) makes this a winner in my book.

It's so addictive, I rolled back Firefox to 3.0.1 so I could keep on using it (not yet compatible with 3.0.3) and disabled automatic updates so I wouldn't have to do that dance step again.

This review is for a previous version of the add-on (1.0.0.15). 

Yahoo Mail Notifier is definitely compatible with Firefox 3.0.3 so there is no reason to roll back to version 3.0.1. In fact I HIGHLY recommend that you don't do that since 3.0.1 has security flaws in it.

BTW the extension is also compatible with the latest Firefox 3.1 nightlies as well.