This extension actually works, however, It is almost impossible to locate the real downloading URL location/button because the author has liberally added adverts which look as though they would be the download URL for this (good) firefox add-on. For instance, I just received an email touting an improvement to this add-on, but was unable to locate the download url to it.
UPDATE: improvements no longer have to be downloaded, since they automatically are installed by this extension.
If you can find the URL for the Author's support email, you will actually get a response in about 3 days. My experience is that if you don't give up after receiving the first, generalized response, you will eventually be very satisfied by the author's support, e.g., it took me 4-5 emails to get exactly the information I was seeking.