Alexa Internet, Inc. is a San Francisco-based American web traffic research firm. It is a wholly-owned branch of Amazon.
Alexa was established as an independent company in 1996 and purchased $250 million in equity by Amazon in 1999. Alexa offers traffic statistics, global rankings and other information to more than 30 million websites.
Alexa's traffic forecasts are based on data from its worldwide traffic panel, which is a survey of millions of Internet users using one of the different browser extensions.
In conjunction, Alexa receives a large portion of its traffic data from direct sources in the form of sites that have opted to implement the Alexa script on their web and to certify their metrics. However, site owners can often opt to keep their accredited metrics confidential.
Alexa's worldwide traffic rating is an indicator of how the company has been performing compared to all other websites for the last 3 months. The rank is determined using a patented formula that incorporates the site's approximate average number of unique users per day and its estimated number of page views over the past 3 months.
Alexa has a related country-specific score, which is a calculation of how the website ranks in a given country compared to other pages over the past month.