Alexa, founded in 1996, was taken over by Amazon in the year 1999.
The company’s services are inclusive of gathering data on traffic numbers via browser extensions and toolbars. Websites are ranked as per ‘Alexa Rank’ – a measurement that is based on the site’s popularity over a period of 3 months.
The importance of Alexa ranks lies in the fact that it provides a comparison of your site’s popularity as compared to those of your competitors. However, you can use the Google Analytics tool for assessing the success of only your site.