Alexa rank is a global ranking method to rank websites based on its popularity with respect to other websites on the internet.
It may not be accurate always. Alexa rank websites based on the information they get. It ranks mainly on the number of unique visits, page views, etc...
Even though it's not always accurate, it can be used for comparing one website's performance against any other domain.
Do you know?
We use Alexa rank to calculate the website worth, page views and income.