It isn’t accurate, If you don’t have the alexa toolbar installed you don’t count in it’s statistics.
How many people on this thread have it installed? I know I don’t.
Ignore Alexa ratings.
Alexa had big ambitions early in the “Web 1.0” days to be “Nielsen” of the Internet, but it became - and still is - considered to be a spyware (”trackware”), and is routinely removed from machines by various anti-spyware and anti-virus programs. Alexa disagrees, but their distinction supposedly is that spyware is installed on your machine without your knowledge and for nefarious purposes, whereas they let you know if you choose to install it, toolbar is displayed and can be turned off by user at any time or simply uninstalled. Also, Alexa toolbar is only used with IE browser, not Firefox, Mozilla, Opera or any other (though that is still a relatively small percentage, it’s quite possible that some sites could have a large proportion of their traffic from people using alternative browsers and thus would not be measured.)
Nielsen Media Research (subsidiary of Nielsen, former VNU) is now working to avoid these pitfalls, to that end this year it acquired full ownership of its subsidiaries NetRatings and BuzzMetrics, and is trying to install metering at points of entry for accuracy, but does not entirely rely on this method for sites who don’t use their metering.
Got me?