Update: Ah, I see somebody already pointed you to it (http://arclanguage.org/item?id=3919). The point of the UI is that new replies to threads you were involved in will show up in reverse chronological order with all their context (parent comments).
I actually didn't click through on lojic's comment, I'm sorry to say, from "old news" I assumed the link was to someone else complaining about the same thing, not pointing to a fix!
Thanks! Unfortunate that news.yc went through a revision on the day you became aware of hystry. Hmm, perhaps I should crawl arclanguage and news.yc with separate crawlers even if it's the same code.
(Ulterior motive in writing this reply: to make sure parent gets crawled by hystry after restarting :)
There are two "comments" links, one at the top of the page for all new comments, and one at the bottom of your profile page for all comments you posted.
I find the personal "comments" page very useful for finding all responses to comments I posted.