The same as anything that makes it to the frontpage - it's of interest to a nontrivial number of members, as determined by the algorithm.

It's not like HN has a mandated theme, it's just a bunch of people interested in somewhat similar stuff.

How does HN even know that there are enough people interested in CK2?

Nevertheless, CK2 is an amazing undertaking. I never really played CK2. I used to play KOEI's Nobunaga's Ambition and Romance of the Three Kingdoms. Those games are focused on relatively short spans of history, and there are not nearly as many "characters" as you can play in CK2. So when I compare, between CK2 and KOEI's games, the amount of effort given in historical research, in trying to find interesting historical figures for people to play as, and in coming up with all the different game mechanics for the characters' stories, it's just unfathomable.

People submit stuff and if "hn finds it interesting" it will be upvoted and rise. Of not, it will just go away. Honestly it's a lot more on the people that browse the new section that most of the public.

> determined by the algorithm

This sentence makes me shiver

All sorting is algorithmic. Sorting by submission order is an algorithm.

Regardless, we don't have to speculate since the site is open-source. You can see the sorting algorithm, and a breakdown of it, here[1]. It's just number of votes and time decay.

[1] https://medium.com/hacking-and-gonzo/how-hacker-news-ranking...

Why?

The references are based on actual historical figures. We've been known as a community to enjoy bits of entertaining historical trivia now and then. And that page is very, very entertaining.