[aaco]

> Simple test: if there were more comments like this, would HN be a better place? If yes, upvote. If no, downvote. If indifferent/not sure, move on to next comment.

I agree with you here. The problem is that this is not directly obvious by only observing the upvote arrow. It might communicate more things than this, like "I agree with this comment." So, unless you tell them (and keep reinforcing this meaning), different people will read it differently.

I would even argue that it would be a good idea replacing the upvote arrow with a link named "I want to see more comments like this". That would stimulate more well thought, relevant comments, while agreeable/funny comments would still be there, but at the bottom of the page. These might be harmless, but they don't deserve lots of upvotes.