[Potentially inaccurate content removed by author]
HN automatically combines submissions so that subsequent submissions count as upvotes for the first submission.
If a popular source posts a new article, users will "rush" to post it to HN to reap that sweet karma and the winner will "catch" the upvotes of the others.
Is this behavior documented anywhere on news.ycombinator.com?
https://news.ycombinator.com/newsguidelines.html
and
https://news.ycombinator.com/newsfaq.html
and a handful of posts by dang, sama, pg, etc. over the course of the years. most of the rest is what long-time users have just figured out through observation. There's a Git repo[1] out there that aggregates a lot of that stuff, but keep in mind that it's technically unofficial. That said, I think most of what's there is widely considered to be correct.
I can't find any reference to something like "combine the scores of new submissions of the same URL to the first submission's score" though. I guess that's either new information or incorrect.
I think that falls into the "noticed through observation" bucket. I'm relatively sure that it is correct, as I've noticed that behavior myself. But, I have no official standing here and I could be totally wrong. But that sure seems to be what happens in my experience.
Not automatically.
It's the HN algorithm which is probably due to the fact that other posts from his domain have done relatively well, plus the actual poster here has quite a bit of karma.