Yes! A "last touched" thread view is useful for finding active conversations. I'd also keep a separate feed of individual posts: if a thread gets five replies, a thread list only tells you it changed, while the feed shows what changed.

Claude's proposed last-post fields would help clients build the thread view; an individual-post feed needs its own paginated endpoint. Bonus: let people filter out their own activity, so your own reply doesn't make a thread look newly active to you.