BuiltWith Top Sites Rank is a patent pending ranking feature for hundreds of millions of websites - it uses a combination of time and technology spend to create a truely unique rank. It does not use traffic or links to determine top sites. It also does not include sites which have user generated content (like google.com, facebook.com etc..) - you can get the Top 1m sites as a ZIP file here - https://builtwith.com/top-1m