Ask HN: Erratic HN front page algorithm
Last week I had two submissions reach the HN front page. Before that, I assumed the ranking followed a roughly monotonic time-decay curve once a post peaked. While watching these two posts, I noticed something different: their rank would sometimes improve after declining, and occasionally oscillate back and forth (Here is a graph showing this behavior: https://imgur.com/a/AQnSh6I). what mechanisms in the HN ranking algorithm cause this kind of non-monotonic movement. Is it due to vote weighting, comment activity, re-ranking batches, or something else?
The graph is from: https://track-hacker-news.com/
EDIT: This is the post referenced: https://news.ycombinator.com/item?id=46512881 1) Flags ("enough flags will strongly reduce the rank of the submission") 2) Flame-War Detector ("A good rule of thumb for this effect is when the number of comments on a submission exceeds its score.") Quotes from here: https://github.com/minimaxir/hacker-news-undocumented 1) But then why would it come back again.
2) Maybe that yes, but then same question as with (1) The main idea is that they are sorted by "upvotes^2/time" or something like that, but there are a lot of automatic and manual penalties, that can be added or removed by the mods. (Probably upvotes^1.6/(time+1) , but it may have change from time to time, or not, who knows.) I bet if you saw the source code for how the algorithm really worked and what options admins have behind the scenes, will make you vomit.