[rajanaccros]

I think the same logic can apply to your scenario. If it is off topic it gets downvoted by the community and disappears to hidden. The relevant data gets voted up to the top as again decided by the community.

This would inevitably reward first commenters, but that is the situation anyway with current thread voting. I think later commenters as long as not downvoted past a threshold would stay visible with an even(ish) vote count to give those comments the visibility to rise.

What about comments that people disagree with that are still on topic but controversial? Well, we are running out of directions so they should get a side vote. Downvotes to explicitly send to hidden as not relevant (spam, off topic, etc), upvotes for agreeable comments base on popularity, side votes for relevant but disagreeable.

[khedoros1]

Things that are off-topic and illegal aren't the only ones that get downvoted, though. HN is unusual in the sense that it's discouraged to downvote things you dislike; that's the effective status quo in most other communities. In your proposed system, you'll have some people side-voting those comments, and you're going to have others downvoting them.

[Jcowell]

it’s not discouraged. people flag and downvote things they don’t like as well. the difference is that newcomers don’t have the ability to until they get a certain level of Karma.

[ShellfishMeme]

The thing is thought that through discovery and feeds it happens often that a much larger amount of folks than the ones belonging to the core community flood in. Downvotes alone won't work because nobody knows how things are supposed to work.

If you have a costume party with 100 people and 10 arrive without costume, they are the outsiders that have to adapt. If 1000 people join your party you're the weird minority and your costume party will be over.