Yahoo's fault, not YMN Rated 4 out of 5 stars
This is an excellent add-on and it only seems to have stopped working properly since Yahoo switched to the new mail version. How many people have been using this for years and only decided to rate it (poorly) now because it's temporarily broken?
Great add-on, keep up the good work!
The link the author has posted has an extra character, which is why the Mozilla says it can't find the page you're looking for. Just remove the ) from the end of the link in the address bar: