How on Earth can Cloudflare make money?
Well it's like this: they sell information about you.
CloudFlare Privacy & Security Policy
... In order for us to provide some of the services we do we may on occasion need to provide information you supply us to external parties. ... As visitors browse our web site, or your sites if they are protected by CloudFlare, we sometimes track them ... CloudFlare may aggregate data we acquire about you and the visitors to your site. ... we assemble this sort of data and provide it to external parties ...