Rated 4 out of 5 stars

Well, it definitely does what it's meant to do. I'm not sure why, but this extension gives me problems (tells me that the username/password combination is incorrect) sometimes - though this can be fixed by switching to one of my account alibis. If you're using multiple Yahoo accounts with the same installation of Firefox, don't forget to right click > logout before signing on as a different user! I got logged out several times before realizing this.

This review is for a previous version of the add-on (1.0.0.16).