Site owners who install the Alexa Certify Code on their website can choose to display their Certified Metrics, such as Monthly Unique Visitors and Pageviews, if they wish.
Not all websites implement our on-site analytics and publish the results.
For these sites, we show estimated metrics based on traffic patterns across the web as a whole.
We identify these patterns by looking at the activity of millions of web users throughout the world, and using data normalization to correct for any biases.
The more traffic a site gets, the more data we have to calculate estimated metrics.
Estimates are more reliable the closer a site is to being ranked #1.