As the author of the post, I can confirm it is legitimate (poop emoji dot st). I was hoping HN would allow it to come through as emoji instead of punycode, but

As the author of the post, I can confirm it is legitimate (poop emoji dot st). I was hoping HN would allow it to come through as emoji instead of punycode, but tripped some kind of inapplicable server error. It (an emoji domain) does pose a corner case of a problem for them (HN), so I haven't brought it to their attention yet.