what is alexa ranking ?

It is a metric that categorizes websites based on their traffic and poularity.

The Alexa rank gives a website ranking in terms of the volume of web traffic coming to the website. Alexa is the one that measures the volume of web traffic that is used to determine the ranks. The Alexa rank is calculated based on whether internet users have the toolbar from Alexa installed or not, amongst other factors. It is useful but not as Google rankings.

The Alexa rank is a metric/measurement that looks at the traffic that coms through the website. However, Alexa offers a bit more than that because it offers tabs that can be displayed on the browser. These tabs display some useful information such as traffic for page or for the domain that indicate how popular the site is. It is useful but not essential.