[bct]

> So why is every text editor I have ever seen embedded in a website an abomination?

Because most websites use contenteditable for their rich text editors, which is horrible to deal with. It's not standardized, it gives developers very little control, and its output and capabilities vary a lot from browser to browser.

Web rich text editors that don't suck - e.g. Google Docs - bypass the browser's support for rich text editing entirely. This makes them usable, but it also means everything has to be implemented from scratch, so the code is complex. AFAIK there are no general purpose rich text editors built like this that are open source or even licensable.

There are some pretty good non-contenteditable code editors, though. Presumably Atom will be built in this style.