Alexa is a company of Amazon.com which is well known for their toolbar & elegant website . Alexa has Its toolbar which is available for various web-browsers whether it is mozilla firefox , internet explorer , chrome. Alexa toolbar collects whole informations from website & provides the accurate rank in their website.
Alexa Toolbar ->
Toolbar for Internet Explorer ->
Alexa Provides the accurate ranks over the internet , I would really recommend you to install alexa toolbar for having accurate rank of your website.