I don't think it's splitting hairs at all. When you have a centralized point of failure (e.g. datacenter) backend that runs the show, you're not 100% client-side. You're probably not even 10% client-side.

And as Amazon has shown us, you're not infinitely scalable either when a routing misconfiguration wipes your service off the face of the internet.

That said, I wouldn't be so passionate about the topic if I weren't working on a true serverless client-side app framework :).

Any website could fail because of router misconfiguration, BGP errors (see Youtube), or DNS issues outside of your control.

The point is that it won't fail because of me. I don't have to optimize SQL queries or launch new instances or rewrite my backend in C. It just works, for 1 user or 1 billion.

You still need to serve a static HTML page, even if most of the body content loads from elsewhere. Serving a small static HTML file certainly scales well, but not infinitely.

Agreed. Infinite might not be the best word choice, but this site scales as easily as possible, and as well as the Facebook and Youtube API's.