[jgrahamc]

Yes. A lot has changed since then. Including a whole lot of stability and expansion. I think you'd have a different experience today.

In general, is it useful and/or recommended to use CloudFlare in front a fully dynamic service, for example a HTTP-JSON API, with no static content (no images, no stylesheets, no scripts), and thus no need for the CDN feature?

We do have lots of customers who do that. Two reasons: Railgun and Security. Railgun gives speedups for the JSON because of the ability to diff the boilerplate JSON. Security for APIs is of course important and clearly attackers like to go after APIs.

[ngrilly]

I have difficulties imagining what can I gain from the JSON "diffing" made possible by Railgun: could you provide an example?

About security, what are the specific security features you're thinking of?