Alexa was once a useful tool for webmasters. Now they only provide accurate information to those who pay and it seems even penalize the sites of those who don't.
My site has increased in legitimate traffic week over week, month over month for the last 4 months yet my highest Alexa rank was 4 months ago (95k). Since then my rank has dropped to the 130ks and held there. SO either Alexa was horribly inaccurate before or it is penalizing site owners who don't now pay for the service...
It's sad what Alexa has become, I remember when it used to be the gold standard of site metrics.