How accurate is Alexa for traffic measurement?

Here is the deal. 

If anyone would like to send me an email

- email subject Alexa ranking
- visitor sessions per month (not unique visitors) for a recent month
- alexa ranking - 3 month average (better than 200,000)
- No need to mention the name of the site but indicate if it is b2c or b2b

I will post it onto this graph

http://dev.textor.com/alexadata/

I have three points at present, I guess if we can get 10 we will know if there is any sort of statistically significant trend at this end of the graph.

If you don't know how to get the alexa ranking do a search for your domain on www.alexa.com and then click on 'see traffic details.

Tell your friends.

Bob
Textor