"I think these questions at IAC are great, it's good that people get a chance to <self promote thing> at a technical conference"
"Wtf is with these stupid questions at IAC? They should be asking about <fascinating technical detail>"
i.e.,
"I think these questions at IAC are great,..."
"...they should be asking about <fascinating technical detail>"
"I think it's a good idea to start a national wingsuit base jumping team."
"I don't know if that's a good idea. Pretty high chance of death"
Penalized - negative post
But it could be useful to look at the comment history of a user. When someone who is an overall positively minded contributor (with a high average positive sentiment) suddenly writes one scathing reply, this could mark a potentially interesting thread.
I just want positive comments to appear as the top comment more often.
Negative commenta should have a bit of a higher bar (in other words, need more votes) to get to the top
What if HN included sentiment in the sort algorithm?
The post score you see would stay the same (upvotes minus downvotes). You'd just multiply the sort score by, for example, 1.25 for posts positive in tone and 0.8 for posts with negative tone.
So if two comments have about the same number of upvotes, the nicer one appears higher up.
Criticism or disapproval could still become top post with enough upvotes, but it wouldnt happen as often as it does now.