Alexa Internet: Alexa Internet, otherwise known simply as "Alexa", is a California-based subsidiary of Founded in 1996 and acquired by Amazon in 1999, Alexa provides website traffic measurement services. This is accomplished by their toolbar, which collects information on browsing behavior and transmits it to the company's website, where it is stored and analyzed. As of 2014, Alexa claimed to provide traffic data, global rankings and more for 30 million websites. They claim that their website is visited by over 8.8 million people every month.

Named for the famed Library of Alexandria, Alexa was founded by American computer engineers and entrepreneurs Brewster Kahle and Bruce Gilliat. While Alexa was originally intended to function as an "intelligent" search engine, the company began shifting their focus shortly before they sold to Amazon for $250 million of the corporation's stock. Afterwards, Alexa initially formed partnerships with Google, the web directory DMOZ and Live Search, and released an application called Alexa Image Search.

The company officially switched to measuring website traffic in 2005. Today, Alexa is known for being heavily biased towards sites which focus on marketing, as well as webmaster communities. However, while it is not heavily accurate, the service is free.