"The Great Cloudwall" is [CloudFlare](https://www.cloudflare.com/), the world's largest MITM proxy([reverse proxy](https://en.wikipedia.org/wiki/Reverse_proxy)).
It is called this in reference to the [Great Firewall of China](http://www.greatfirewallofchina.org/) 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"](https://en.wikipedia.org/wiki/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 multiple image CAPTCHAs. Cloudflare also has a massive harassment problem. [Tor users](https://www.torproject.org/) and VPN users are a victim.
