About WebChartz

WebChartz generates charts of website popularity trends using data from Alexa Top 1M and Cisco Umbrella Top 1M, assuming inverse relationship between Rank and Popularity (# of Visitors).

A general assumption is made that approximate # of visitors on a website is ~ 1,000,000,000 divided by the Rank. For example, Google with Rank 1 will have 1bln visitors. A site with rank 1,000 will have 1bln / 1,000 = 1mln visitors, and so on. In most cases such assumption results in less than factor of 10 error.

Data details:

1) Amazon used to have Alexa toolbar which collected information on website usage with reports being available in 2009-2023. This data was technically skewed toward general audience that used such toolbar, which would be more tech-savvy and business oriented.

2) Cisco Umbrella started releasing their data in 2017. Cisco uses summary from their network equipment which is not skewed by user type, however it has "noise" from advertising and CDN servers which do not host websites. The first few months of Cisco Umbrella data also had slightly different ranking and are ignored. Cisco list is available here.

3) WebChartz averages ranks during each week and uses this average for charting.

4) For charts between July 2017 and present, WebChartz only uses data from Cisco.

5) For charts where data is used before July 2015, an "alignment" algorithm is used to scale ranks from Alexa to match ranks from Cisco between July 2017 and July 2018.