The Great Cloudwall
The Great Cloudwall is CloudFlare. It is called this in reference to the Great Firewall of China which does a comparable job of filtering out some people from seeing web content(ie everyone in mainland china and some people outside) while at the same time those not affected to see a dratically different web, a web free of censorship of such images as "tank man". Cloudflare similarly prevents those in southeast asia and elsewhere who have poor internet connectivity from accessing the websites behind it(for example, they could be behind 7+ layers of NAT) unless they solve a CAPTCHA.
This repository is a list of websites that are behind The Great Cloudwall, websites who human beings have tried to access and have been either blocked from or suspect they will be. Or Cloudflare's competitors.
There is more details of why what they are doing is wrong available here.
See FAQ for Frequently Asked Questions
What can you do?
There are other lists, but this one is one where every entry on the list a human being has actually tried to go to, and has been blocked.