Sadly, Paul Graham has endorsed the idea of using the downvote to express disagreement. I personally dislike this use of the downvote, but it does have official sanction. Read this:

http://news.ycombinator.com/item?id=117171

Just because something CAN be done doesn't mean it SHOULD be done. I think the community benefits from people expressing counter-arguments far more than grey-ing out minority opinion.

I'd hope a majority of users here feel the same way and act accordingly - pg's comments not withstanding.

> I think it's ok to use the up and down arrows to express agreement.

There's a dangerous consequence to saying this. Here's how: 1. Voting is easy.

2. Voting is valueable: it literally changes HN for everyone else.

3. Agreement/disagreement is easy: we're taught how to do it as children.

4. Agreement/disagreement is value-less. Saying that you agree with pg on 'Hackers and Painters' is valueless. Saying "prior to reading H&P, I was in mindset A-B-C supported by points of view D-E-F, and here's how they were modified, and here's the new mindset H-I-J" conveys the same agreement, but it provides value.

We shouldn't incite people to use up/down votes to express something value-less. Agreement and lack thereof (alone) is valueless.

> I thought down-votes were only for things that didn't contribute to the conversation.

yeah, well.. you need to see my posts on Apple threads.

Some people might have downvoted based on the DMV example apparently being wrong. Factual inaccuracy can be a good reason to downvote.