Cloudflare does way more than just cache pages. As I said, they can also filter requests, even going so far in extreme cases as to use a captcha to validate that the one making the request is human before forwarding the request upstream to the origin server.

I've never used 8Chan, but my understanding is that it's a simple forum site, like 4Chan. That seems at a cursory glance to be feasible to run in a distributed manner; though I guess it depends on how the application itself is architected. That's kinda irrelevant though, since as I just explained a well designed CDN like Cloudflare can remove a lot of the need for the site itself to implement a distributed infrastructure. (At least so long as DDOS is the cause of your scaling issue, and not legitimate traffic.)