Ranks and Authorities

##Alexa traffic rank

A rough estimate of a site's popularity. Rank is calculated using a combination of average daily visitors to the site and pageviews on the site over the past 3 months. The site with the highest combination of visitors and pageviews is ranked #1.

https://support.alexa.com/hc/en-us/articles/200449744-How-are-Alexa-s-traffic-rankings-determined

##Alexa traffic rank in country A rough estimate of a site's popularity in a specific country.

Rank by country is calculated using a combination of average daily visitors to the site and pageviews on the site from users from that country over the past month.

The site with the highest combination of visitors and pageviews is ranked #1 in that country.

https://support.alexa.com/hc/en-us/articles/200449744-How-are-Alexa-s-traffic-rankings-determined

##Google Page Rank [DEPRECATED]

Google Page Rank is a link analysis algorithm used by Google that measures how many links point to a website or page, and more importantly the quality or importance of the sites that provide those links.

It uses a numerical scale, with 0 being the least important and 10 being the most important.

https://en.wikipedia.org/wiki/PageRank

##Moz Domain Authority

Domain Authority is an aggregate score (0-100 scale) based on Moz's numerous linking metrics that predicts how well a website will rank on search engines. Domain authority is used to compare sites or track a site's "strength" over time.

To find out more, see: https://moz.com/learn/seo/domain-authority