Do you use reddit?

As cookingrobot says, gmails threading is one dimensional and super clunky when you have lots of replies. It auto collapses to far so you can't easily reply to a particular message in the thread.

Reddit has the best comment threading system of any site online. Quora is near the worst. HN is just slightly frustrating.

I thought reddit and HN were using the same system. What's the difference?

Hacker News is written in Arc, a dialect of Lisp: http://en.wikipedia.org/wiki/Arc_(programming_language)

Reddit used be written in Lisp, but they switched to Python early on: http://blog.reddit.com/2005/12/on-lisp.html

I do agree that they look alike, Hacker News was inspired by Reddit.

Not the same exact software, just the same way of representing comment threads.

Collapsing threads, for one thing.

It's like, one line of javascript different (the equivalent of if score < threshold: thread.collapse())

I don't care about the code. Collapsing is a significant change in UX.

EXACTLY!

No one seems to get this, not HN, not Quora, Digg (though that doesn't matter any longer...)

Its about increasing the information consumption rate and navigation rate. Collapsing is critical to navigating threads with thousands of comments, even tens of comments!

Any UX designer who does not see this, is, in my book, worthless.

Inspect the source for both sites. I have to admit, I felt a little nauseous when I first read HN's markup & styling.

But when you open a message with lots of replies, there's no structure, and you can't reply to one person's comment (like I'm replying to your comment here). This would be messy in gmail.

  > you can't reply to one person's comment

You can, but it doesn't maintain proper threading. It just groups them all together and sorts by date.

As in Google Groups?

You think that google groups is an analogous email client?

No, but Google Groups brings the innovations mentioned above to email lists, so it's an analogous comparison.