I am fairly certain, that I am not currently visiting ssl318873.cloudflaressl.com.
But that just happens to be the domain for which the SSL certificate, that, when visiting https://forum.teksyndicate.com, I get sent to me. Setting up LetsEncrypt takes like 5 minutes =P
CloudFlare, Inc. is a U.S. company that provides a content delivery network and distributed domain name server services, sitting between the visitor and the CloudFlare user's hosting provider, acting as a reverse proxy for websites.