These are traffic rankings up to 1m from four different sources of traffic ranking providers. The lower the number the more traffic the site gets in general. We provide all four because they are all very different.
Alexa’s rank is based on browser extension tool bar uses and other sources – https://www.alexa.com/topsites
Quantcast rank is “websites based on the number of people in the United States who visit each site within a month. It includes sites with estimated traffic as well as sites with traffic that Quantcast has independently verified. Quantcast directly measures site traffic through the implementation of the Quantcast asynchronous tag on each web site.” – https://www.quantcast.com/top-sites/
Majestic is a rank based on the most referring subnets – https://majestic.com/reports/majestic-million – note we have removed subdomains from this list – i.e. docs.google.com isn’t counted and we remove that site from the list, lowering the numbers for sites below it.
Umbrella is based on net sum DNS queries across the globe – https://umbrella.cisco.com/blog/2016/12/14/cisco-umbrella-1-million/