The Alexa toolbar is a great myth possibly spread by the company itself, who knows... I never believed that a toolbar will improve your rankings. Think of it logically, how does an installation of it on your local machine will make a difference for the hundreds of millions of other computer users around the world?
If you are looking to gain better rankings, you have to follow the social road and get on every popular social network, including Google Plus. Actually, especially Google Plus now that they are integrating the results of it in the search engine.