The Alexa Traffic History Graph allows you to create a
traffic history graph for any site. Alexa computes traffic
rankings by analyzing the Web usage of millions of Alexa Toolbar
What is Traffic Rank?
The traffic rank is based on three months of aggregated
historical traffic data from millions of Alexa Toolbar users. It
is a combined measure of page views and users (reach). The
three-month change is determined by comparing the site's current
rank with its rank from three months ago.
What is Reach?
Reach measures the number of users. Reach is typically expressed
as the percentage of all Internet users who visit a given site.
Alexa expresses reach as the number of users per million. The
three-month changes are determined by comparing a site's current
reach with its values from three month ago.