Then upvote/downvote are the wrong semantics for what you are proposing.
Change them to "like" and "spam". For a multi-lingual audience, that is easier to grok than to hash the up/down arrows.
I'm not proposing anything. "Upvote" and "downvote" are the names given to functions of the HN site. My descriptions of those words are my understanding of the consensus among HN users on what they mean and how they should be used. If my understanding of that consensus is wrong then I hope that others users will put me right.
Edit: Would whoever downvoted this care to explain why? I'm genuinely interested.
Ignore the downvotes. Unless you get more than one.
It would be nice if Upvote meant "This is good quality (whether I agree with it or not" and downvote meant "this is low quality, and should not be here, but is not spam, nor flagable". But since PG has said (something like) downvote can be simple disagreement you're going to meet people who use it for exactly that.
Also, reddit is trying to move away from "downvote to disagree" - they have a lot of hover text saying this.
I agree, but I also believe a little ambiguity and heterogeneous modes of use are actually beneficial, make the place alive.
I tend to up-vote people who make efforts and contribute important information or opinions, not necessarily those I agree with. (Will only down-vote trolls.)
