I was not only referring to HN but the many communities that employ up/down voting. And for the record, I disagree with pg's take. Here is Reddit's official stance on downvoting:
>Think before you downvote and take a moment to ensure you're downvoting someone because they are not contributing to the community dialogue or discussion. If you simply take a moment to stop, think and examine your reasons for downvoting, rather than doing so out of an emotional reaction, you will ensure that your downvotes are given for good reasons.
https://news.ycombinator.com/item?id=16131314