It's a metaphor. The excuse I keep hearing is that if we learn how HN filters spam, it will enable spammers to game the system.<p>Frankly, I don't care so much about the internal mechanisms used to kill posts. I just want to understand the policy; I have the showdead flag on and at least a quarter of the time, I can't for the life of me figure out why a comment was killed. That lack of transparency makes me uncomfortable.