I frequently see people describe HN and Reddit as 'fickle' or 'hypocritical'. But the underlying pattern seems to be a nasty consequence of point-based ordering: whatever comes first does best.

There are some great breakdowns of Reddit comment karma by time after post. The direction is obvious - earlier comments score better - but the exponential falloff is still a sight to behold. Any view that isn't outrageous enough to downvote heavily can win just by arriving first, being seen most, and being upvoted by commenters trying to increase their own engagement. (HN removes 'downvote' when people reply to you. I wonder if it should discount upvotes on comments you reply to?)

It's a less-trolled system than the open queue of a messageboard, and more conversational than the obscure branching pattern of Twitter or Tumblr. But it's not much good for comprehensive, noninflammatory discussion.