Many good points. I'd like to add a common open secret that I believe is wrong: 1 upvote = 1 karma point.
This might be true internally and initially, before any ant-spam, anti-upvote-ring detection takes place. Effectively, from a user point of view it is not - at least for me.
When I look at the points one of my submissions get and compare my increase in overall karma it is very roughly 50% most of the time. Needless to say that I never participated in things that would be considered unethically (voting-ring etc.). Also not a complaint at all, just an observation that goes against what is often written in "about HN" type posts (but not OP).
EDIT:
1. My observation is from more than a year ago, so things might well have changed.
2. As lordnacho points out below this seems to be true only for stories. Regardless why it happens, awarding stories with less points than comments makes a lot of sense to me. After all posting a suitable story is much less effort than writing a decent comment.
Do you mean on stories? I've noticed upvotes on stories don't give you 1 karma each, it's less. Not sure if it's a linear 0.5. But upvotes on comments seem to be 1 each.
I think the karma from a story is more or less capped to the number of comments on the story. At the same time, a story which gets more comments than upvotes quickly vanishes from the front page.
This is an interesting idea and another rabbit hole to fall into. There are this uninteresting posts that never get any attention (no upvotes, no comments) and there are the popular posts that get a ton of upvotes and comments. That much is understood.
Occasionally, though, I have this post that gets a decent amount of upvotes but not a single comment. I never understood why. I post for the comments and not for the upvotes. It is very frustrating, especially since it is a miracle to me what distinguishes these posts from the popular ones.
Capping the points on these makes a lot of sense though. In the end they don't contribute much.
This is far and away one of my favorite metrics. If I see something with more comments than upvotes on here, I can expect an intense debate over something controversial. These tend to be some of my favorite comment sections.
my observation is that when you are starting out your stories generate more than .5 per comment, not sure if it is 1 per comment, but at a certain point you get capped to .5 per comment on story. Have not noticed any capping on favorites for comments though.
Yes, I observed it on stories. I don't remember if I ever looked into comments. Also my observation is from more than a year ago, so things might well have changed.
My bet is that some upvotes don't count either for your karma nor the karma of the post. And the upvotes that don't count are from account which HN considers as bots.
This might be true internally and initially, before any ant-spam, anti-upvote-ring detection takes place. Effectively, from a user point of view it is not - at least for me.
When I look at the points one of my submissions get and compare my increase in overall karma it is very roughly 50% most of the time. Needless to say that I never participated in things that would be considered unethically (voting-ring etc.). Also not a complaint at all, just an observation that goes against what is often written in "about HN" type posts (but not OP).
EDIT:
1. My observation is from more than a year ago, so things might well have changed.
2. As lordnacho points out below this seems to be true only for stories. Regardless why it happens, awarding stories with less points than comments makes a lot of sense to me. After all posting a suitable story is much less effort than writing a decent comment.