[JoelBennett]

In that regard, I've been kind of curious to know how Hacker News deals with comments. It seems like there's only a single upvote button (no downvoting), and you can't see how much something has been upvoted. It kind of kills the popularity contest part of things.

The whole psychology of online commenting and having groups rate things is quite interesting.

[Yen]

I believe there is a 'downvote' button, but it's only available once you've scored above a certain karma threshold.

Also, while you don't know how often something has been upvoted, a comment with a higher score will be at the top of the page, and you'll see it first and be more likely to give it an additional upvote.