https://radar.cloudflare.com/domains
Source of this is from Matthew Prince, Co-founder & CEO of Cloudflare posted at 11:34 Jul 9,2023. It was posted to his twitter (@eastdakota). Not linking to twitter bc don’t want a deadlink next time twitter makes API changes. And not to drive traffic to twitter :D
Edit: July 11th update, arstechnica published a detailed explanation
It measures the most popular sites by dns lookup. Twitter fell from 32nd to 39th.