Hacker News Reader

Yup, and Reader mode on Firefox Mobile is disabled. Couldn't read more than a few sentences.

Just out of curiosity, what controls whether or not reader mode is enabled?

I believe it is a heuristic that looks at text length, element type and class name.

Yup! It looks for paragraphs that are at least 140 characters long. I wrote about it a bit more here: https://videoinu.com/blog/firefox-reader-view-heuristics