[u801e]

I actually prefer having the thread with the most recent post at the top (or bottom depending on how one sorts it) of the list. That, I find is helpful in terms of keep up to date with the most recent comments. The equivalent in HN would be that the next time you load HN's front page, this particular article would appear at the top of the list and this comment (along with other new comments) would be highlighted when you load the comments section.

Thunderbird does this by default. Reddit breaks threading when sorting by "new". On HN, you have to search the comments page "minutes ago" or "hours ago" to find new comments in an existing thread.