Why were a few rank numbers black on the homepage?

Question

The HN homepage has five ranks colored black rather than gray. Currently this is "Learning how to ride a bike", "Log4j: Between a rock and a hard place", "How to train your decision-making AIs", "Carolina Gold was once the most popular rice grown in America (2019)", and "Packaging for instant coffee made out of seaweed". It seems to follow the story, e.g. the bike story was #12 before and now it's #13: the color moved with it. They do not have in common a recent/old submission time, high/low score, or high/low comments.The HTML difference is `$rank` being inserted around the rank.It also shows up in incognito mode with the same ones colored black, so I don't think it's account-related.(Some rambling follows, I'm not actually serious about a secret hidden meaning, just a toy idea. Most likely it's something like low comment downvotes to attract attention to the story.)My first thought was that the numbers had a hidden meaning as a puzzle or respect, maybe someone died who invented the equivalent of a Fibonacci sequence. Looking in the OEIS, 1,4,6,12,18 did not mean anything obvious (http://oeis.org/search?q=1%2C4%2C6%2C12%2C18). Then I noticed the numbers changed... but not pseudorandomly, but with the stories, so it seems that the numbers are irrelevant. Is it about the title? If you read the first title character of each, you get LCHPL. If you read the 1st character of the first, the 2nd character of the 2nd, etc., you get LAWKN. Not yet seeing that hidden meaning.Edit: To everyone saying a hot indicator, I thought of that and it doesn't seem to make sense. E.g. go to page 3 and observe this one being black:> 4 points by [user] 7 hours agoThere are currently (22:47 UTC) actually 3 black on the third page, which seems a bit inconsistent with what I saw earlier (earlier: first page had 4, next page had 1, next page had 0).

dang · Accepted Answer

Oops, that was supposed to be moderator-only. There are lots of complexities like that in the mod UI to help those of us whose job it is to stare at the front page. (I've done a s/are/were/ to the title above to preserve its accuracy.)
In this case, the rank was black when it was the highest rank reached by the story so far.
I'm trying to figure out good visual ways to make use of the information (1) highest rank reached by story; (2) amount of time the story has spent on the front page; (3) amount of time since story reached its highest rank.

Uptrenda · Answer

Whatever feature this is for its too subtle to notice. I would have never noticed the difference without you pointing it out.

edoceo · Answer

Looks to me to be a "hot" indicator. Like lots of recent upvotes.

minimaxir · Answer

On Christmas, the rank numbers alternate between black/green and red.But this isn't alternation. Very odd.

exolymph · Answer

Intriguingly, this post was one of them when I saw it. Lol. Maybe dang will show up to explain.

teruakohatu · Answer

For me it changed each time I visited another discussion page, or maybe just as I refreshed, currently only number 1 is back and it is no longer changing.Edit: after posting this comment #3 (this story) changed to black.

polote · Answer

A post can be black on the front while not be black when reading from /active or /classic. So this not something tied to a post. And it seems to change every minute or something like that

ajsfoux234 · Answer

For me, there were four black-colored stories on the front page, and the fifth black-colored story was #56 on the second page.

hyperpallium2 · Answer

(my guess) those rising faster than some threshold, over some period of time.

sanjuqq · Answer

Since we're talking about the website, does anyone know why the only available theme is flashbang white?

CyberRabbi · Answer

Is HN still written in LISP? I think it&rsquo;s time it&rsquo;s written in a modern type-safe language. You know what I mean.