|Someone is wrong on|
Alexa is a website that collects data on website visitors. Originally, the site only collected data based on the browsing patterns of users who had installed the company's software tool on their browsers. More recently Alexa has claimed that it has expanded its data collection procedure to include additional sources, but the details have not been made public.
Alexa's traffic rankings for websites that reach large percentages of Internet users, such as Wikipedia and Google may be fairly accurate, at least for tracking trends. But the company also reports traffic ranks for their top 100,000 rated sites, often reaching so far into the tails of the distribution that the margins of error would overwhelm any actual potential ranking. Likely any ranking above about the top 1000 is dominated by error and worthless.
Beyond traffic rankings, Alexa has embraced the voodoo of demographic tracking. Based on the few cookies it has access to, the operation system and browser used, Alexa claims to be able to tell a site visitor's age, education level, number of children, gender, and whether the site was accessed from work, home or school. The way this demographic information is supposedly gleamed is not published, but the likelihood that even the most basic information (gender, age, location) is even remotely based on the true population of users is extremely small. The more specific demographic information can be completely disregarded.