Comment by jefftk

Google has written publicly about how this system works: https://developer.chrome.com/docs/crux/methodology/ https://www.google.com/chrome/privacy/whitepaper.html#usages...

This includes only listing publicly discoverable pages, only including data from users who have turned on "Make searches and browsing better (Sends URLs of pages you visit to Google)", and only including pages that are visited by a minimum number of users.