Alexa is a very powerful tool used to rank web site traffic. Find out how your web site traffic stacks up against all your competitors! This is one of the most accurate freely available tools to find out how well your site ranks up against millions of other sites on the Web.

Remember: "The lower the Alexa ranking number the more heavily visited the site.".
Some examples are:

amazon.com (rank 14); weather.com (rank 64); cnn.com (rank 26); google.com (rank 5); Yahoo.com (rank 1).

These rankings are generally consistent with the amount of traffic they have.