[jokermatt999]

I actually found this more confusing. My immediate thought of the up/down arrows was that they'd up/downvote the comments, but they instead take you to others. I don't really get how they're grouped either, since they don't seem to be replies...

[kaizenfury7]

Here's an example of a HN comment with 200+ comments:

http://news.ycombinator.com/item?id=2530963

Here's the same thread in my layout:

http://threadit.kaizenrails.com/discussions/839

[phillipadsmith]

I have to admit, I don't immediately get it. Kudos to you for hacking on comment thread presentation and interaction, however. :)

[kaizenfury7]

The arrows let you cycle through the replies of the above comment. This way, instead of using indentation to indicate a parent or ancestors, you simply look at the comments above. I find it easier than following indentation or indentation lines to mentally juxtapose a comment with its parent and its ancestors.