Alexa traffic rank vs Google Analytics
You may have noticed conflicting estimations between Alexa and Google Analytics concerning a web site’s traffic. Let me be clear from the beginning: trust Google. I don’t mean that you should trust Alexa less than Google: you can and should ignore Alexa completely.
Now that I gave the short answer, let me explain. Alexa calculates the traffic of a site gathering information from users that have the Alexa toolbar installed on their browser. This information is used in order for guesses to be made concerning the popularity of a site. The result can be close to reality or not.
For example, if your site is visited only by 5 persons per day, but two or three or all of them use the Alexa toolbar, the rank of Alexa will make this site seem as popular as sites enjoying a lot more traffic, if visitors of those sites include a large portion who don’t use the toolbar of Alexa. Sites related with SEO are expected to enjoy an Alexa rank much higher than their real popularity, since they are visited mainly by webmasters and in general more people who use the Alexa toolbar.