I believe this kind of work doesn’t share a lot of commonality with the research that readers of HN would do - although it is a very effective tool for some stuff we do.
I think if you’re gonna read it, don’t take it as “the one true way” to take notes. Take what you like and do what works for you.
I'm not sure what your expectations of the "normal" HN reader are but lots of people engage in stuff like creative writing, essays, general research to esoteric topics and so on.
For example I have a notebook I constantly scribble on. I've moved a portion of that scribbling to a zettlekasteln like system to a great benefit - although I just use text files and in a simple onedrive directory structure.
There is now roam, a new fancy tool which does nothing new, but spreads hard with the new generation and connects well with the zettelkasten-terms. And there recently was was a book about smart notetaking, which sold somewhat well with people who seek some solution but don't know much about this space.
https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
There is renewed interest.
In this case a strange new word like Zettelkasten also caused me to look it up the first time i saw it. Which was sometime this year.
I.e. had it been appearing everywhere before, I would have looked it up earlier.
In light of the "graph"-craze I could imagine that we will hear more of it.
That said, it can be helpful for sourcing all kinds of stuff, but still think it is a hipster fad.
edit: some dictionaries suggest that "outliner" is a fitting translation. I don't think that is true due to the hierarchy outliners seem to require.
A fortnight or so ago, I saw a link on HN mentioning 'Zettelkasten' and had to look up the word, because I'd never heard it before. Since then, there must have been a Zettelkasten reference at least every other day.