Very convenient! Rated 5 out of 5 stars

I love the way this little extension works. A letter icon sits on the toolbar and changes slightly with the addition of a red/yellow flash behind and to the left of it when email arrives at the yahoo server. The number of emails is also shown to to the right of the icon. The extension uses the Yahoo! Companion feed to check for new mail so only new messages received since last viewing your Yahoo mail box will be counted as new. For me I also have Yahoo plus account that allows me to have have a POP3 service sent to a mail client. In my case it's Thunderbird. I use Yahoo! Mail Notifier to let me know I have mail in the Yahoo mail server, and use that Yahoo email to prefilter Thunderbird. Let me explain. Since I am a member of a number of yahoo forums I am the recipient of a ton of email. It's much easier for me to effectively view and deal with this forum email in Thunderbird but I like the speed and convenience of Yahoo for my everyday run-of-the-mill email. I also use the Yahoo mail to filter junkmail/spam that gets through the yahoo mail server filers. The way I see it I'm getting the best of both worlds. Even when I push the button to view the mail in Thunderbird I can still have a copy of the email remain on the Yahoo server. The Yahoo! Mail Notifier is simply a convenient aid in my mail processing. I love it!

This review is for a previous version of the add-on (0.9.9.2).