The editor is indeed based on editor.md - I don't believe anyone has claimed otherwise?

Charlie requested me to setup a site with that editor available, so I did so - I configured the server, installed nginx and a FastCGI process (you may ask why FastCGI is needed - it's because the editor is just the first part of the site, more is in the works - though for now you're right that it's mostly from the examples). Since you can not see the backend or the planned features you are making assumptions you should not make.

If I wanted to be pedantic and literal - out of the HTML on that page, only the DIV ID and the chunk of javascript lower down the page is an exact copy, the actual javascript code and the CSS is of course also an exact copy because the site does in fact use the editor.md component.
It also happens to run nginx on top of Debian GNU/Linux - but if it was REALLY needed I suppose I could knock up a custom httpd-only OS kernel (seriously - osdev is a hobby of mine and an httpd in a kernel would be fairly simple).

Would you like a custom steempower OS? I can't promise it'll be as efficient as the Linux kernel with nginx on top, but at least it wouldn't just be using a free, opensource kernel that I merely cloned from. It'll take me a week or two though, and since it is a lot of effort i'd want paid for it, but I can do that if you'd like?
See https://github.com/GarethNelson/Zoidberg for an example of my work in osdev - put on hold right now due to focusing on steem projects, but if you want to replace what Charlie is paying for a couple of weeks i'd be happy to write a webserver OS for you, and then i'll write a new markdown editor so it's all completely original, because how dare anyone use code that was already written when providing a useful service.

Apart from setting up the webserver (and taking care to ensure it'll both be scalable in future and remains secure) I also setup the witness infrastructure and took care of securing that too.

I'm proud to say that BitInstant was never broken into even once despite multiple attempts - the single security issue we had was in fact an issue with our domain registrar that I had no control over. I'm bringing that same attention to detail over here on steem and me and Charlie have some big things planned.