I've always thought Alexa ranks weren't that accurate, but did hold some true value.
Until recently when I opened TellyMix - it gets anywhere from 1,000-3,000 unqiue hits a day now and its Alexa ranking is only around 340,000
Whereas my other sites, such as Awesome styles gets 500-1,500 unique views a day and its Alexa rank is 64,541. Even spyka Webmaster which gets just 300-500 unique hits has a 7 day average rank of 102,871
Yesterday Just Free Templates received 513 unique views yet its rank was 75,008
So to conclude, they mean pretty little because some sites - particularly webmaster, marketing and promotion sites like this - have a lot of users which use the alexa toolbar and firefox addon which inflates the rank.
More "generic" sites - like my TV entertainment one - don't get many - if any - users with the alexa toolbar