In a USerEcho topic, when a user want to answer, he has two options:
This is nice, but the chronological order can be broken (if a new reply to and old comment is posted after the last comment of the topic) and a user can "miss" newest contribution in a very long topic since there is no rendering difference of unread comment (bold for instance) and since last contributions may not be at the end.
This is, in fact, not totally matching the "Oldest first / Newest first" ordering selector.
Then, it could be nice to add another way of displaying the comments with "a flat display" (purely chronological, without any indented structure) along with the current displaying which could be more precisely renamed as "with indentation for sub-threads" or "with indented sub-thread after a comment"...
If you find this suggestion useful, that could come true by reworking the current 2 options of the comment ordering selector into 4 new options: