My guess was always that a post on a particular topic might make someone interested to learn more about that topic. If that person then finds a related link interesting, they are more likely to share it if the original post did well enough to indicate that other members of the community are interested in the topic. In some ways it feels a bit like the meme culture of other communities, where users are more likely to post items that are related to previous successful posts.
The main interesting thing to me is when the “topic de jour” has very little to do with what I’d normally associate with HN (language genealogy, Neanderthals, and ancient currencies are some examples from recent memory).
The main interesting thing to me is when the “topic de jour” has very little to do with what I’d normally associate with HN (language genealogy, Neanderthals, and ancient currencies are some examples from recent memory).