I first ran across it on HN. I have no idea who's running it or why, though the domain seems to have been used by a Knight Foundation grantee a few years back. The contact email hasn't answered those questions (though they've answered a few others), and domain registration is through Perfect Privacy.
If anyone has any information on this, I'd love to hear it. (I'd submitted an HN item on it a week or two back.)
On Chrome/Android, it's what I'm running most long-form content through for reading, as design is simply too annoying (and variable) on too many sites. It's been a few years now that I've said: web design isn't the solution, web design is the problem.
The fact that Medium screws this up is particularly ironic for all the reasons Gruber states.
Even the NY Times is better viewed via outline.com (or https://archive.is) if you want to be able to select and copy text from it. Such as, say, to look something up. Or quote it in an essay.
Otherwise, I see an Internet adpocalypse arriving, sooner rather than later. A browser, or other tool, which simply strips all this crap off and gives a stiff middle finger to site design seems imminent.
For the small handful of app-based sites which really need full app status, sure, throw Chrome or Firefox at them. But most stuff doesn't need that.