What real value does an Alexa rank have?

Alexa rank is not a representative of Market Share at all. I have never trusted any of those stats from Alexa. The rank is determined by the traffic that browses your site with the Alexa toolbar installed and that is so one sided in my opinion. This is what on its website (http://www.alexa.com/faqs/?p=134) - Alexa’s Traffic Ranks are based on the traffic data provided by Alexa Toolbar users and data collected from other, diverse sources over a rolling 3 month period If you are a large website (within top 1000 alexa rank) then statistically speaking ,  you can infer the pecking order from Alexa rank i.e. if you are 998 and your competition is  527 then definitely he is doing better in terms of traffic. However, for anything else, its pretty much safe to ignore Alexa. Here is what it says further down on the same page - Sites with relatively low measured traffic will not be accurately ranked by Alexa. We do not receive enough data from our sources to make rankings beyond 100,000 statistically I wouldn't take Alexa Rank too seriously.