Cloudflare is a service that helps to optimize the performance of websites by handling delivery, security, and speed optimization. Cloudflare also provides exception logging, error tracking, and performance metrics. The service works by caching website content and optimizing load times for websites across different regions.
However, some users have reported that Cloudflare customer support was unreachable, and that there are occasional bugs.
This does a whole host of things around file delivery, SSL, security and speed optimization.