Rated 5 out of 5 stars
Yahoo! Mail Notifier 1.0.3: Didn't work for me. Back with Yahoo! Mail Notifier 1.0.2 with success. I run with FF 17.0.4esr and WinXP SP2.This review is for a previous version of the add-on (1.0.3). This user has other reviews of this add-on.
Upgrade to 1.0.4
1.0.3 was buggy. 1.0.4 should work.