In theory all articles have a "flag" link. If enough people flag an article, then it's killed. That's basically HN's version of a "report spam" button. (I say

In theory all articles have a "flag" link. If enough people flag an article, then it's killed. That's basically HN's version of a "report spam" button. (I say "in theory" because there is either a high karma threshold or the potential to lose the ability to flag articles if it is overused; I am not presently able to flag articles, for example).