Experimenting with Threaded Replies

This feature has been requested a few times, and we are experimenting here to improve the organization and readability of conversations within comments.

Sure, for the sake of temporary exchanges, especially on questions, that are specifically aimed at fixing the corresponding post. And we already have this in the Staging Ground, where it's working well.

But the kinds of comments that merit a lasting presence on Stack Overflow Q&A pages, generally don't merit replies, and certainly don't merit threaded discussion.

The suggestions you link on meta.SE are quite old (the first one is from all the way back in 2009!) and the answers there already explain many problems with the idea. The fact that a certain segment of the user base has persistently wanted something like that, doesn't make it a good idea for the site. The most important idea in those answers is that making the comments easier to use encourages putting more comments on the page, but we explicitly want fewer comments on the page because the entire purpose of a Q&A page is to display the Q and the As, and everything else is secondary to that.

Collapsing comment threads by default is not a solution to this. First off, the valuable lasting comments should still be visible¹.

But more importantly, it just means that people who are trying to find an additional piece of information do more clicking and more parsing of comments - the exact problem Stack Overflow was meant to avoid by its design. Meanwhile, people who want to get involved in the discussion (again, explicitly something that isn't supposed to be there in the first place) are that much more likely to retread existing ground (because they haven't seen the previous comment) and make the sprawl even worse.

All of that detracts from how Stack Overflow is designed to work: if reading an answer motivates a different question, go find that question, or ask it if it doesn't already exist.²

_{¹ But those comments should still be de-emphasized relative to the answers - which is a big part of why people so strongly dislike the previous comment experiment. Please: when the community tells you that something is a bad idea, don't just start building on it.}

_{² And of course, comments motivated by questions will generally be those aimed at understanding the question, and thus at fixing the question to meet standards. Notice how, when questions from the Staging Ground are published to the main site, the comments are not migrated? This is one of the key reasons why the Staging Ground works well. Please learn from the one really good thing the company has implemented in the last several years.}

How is flagging going to work with the new nested comments?

If I flag a comment as rude/abusive, but it has replies, do those replies get removed with the parent? Are entire threads removed if the parent is deemed to meet removal criteria, regardless of whether a nested comment might stand on its own merit?

Consider a situation where someone makes a legitimate comment but does so in a rude/abusive/unfriendly way. There are threaded replies that are added in response to the legitimate comment, but the parent itself should be removed because it violated SO policies.

Or a situation where there's a clarifying comment added asking for some particular details. In the underlying thread, some additional comments bring up additional points. The parent comment is addressed via post edits; the nested comments are outstanding. The parent comment can legitimately be removed as no longer needed, but the nested comments might not.

Please add a UI feature to allow collapsing comments at a per-nested-level basis.

This is especially critical given the new UI design increases the space each comment takes up on the page by 2-3x as much. Regardless, if, one comment deep, a reply gets 30 back-and-forths that are unrelated to the answer or original comment, I don't want to have to scroll past them just to see the second top-level comment.

I want to bring balpha's userscript to your attention. While it's not ideal (mainly because there's no data to identify how to link up the comments, besides scraping the mentions, @), it's far superior to the current plan of cluttering the page.

• Add a small reply button,
• record which comment is being replied to,
• then use the same indentation approach.

This solution is both sufficient and effective, without wasting so much space and taking our attention away from the actual Q&A.

My opinion on threaded replies themselves

It's a good idea on paper, it's true that comments are often heavily disorganised, often by an OP trying to reply to other comments one by one, and comment posters replying too in a different order, resulting in a very spaghetti-ish comment section.

But, I feel like they should display the way YouTube does it, with a max depth of one.

This way, if someone comments, replies to this specific comment will be padded to the right a little and put underneath it, but if people keep replying to each other, you're not gonna get a diagonal line of comments.

About the way threaded replies were introduced without taking any previous feedback into account

It feels like you are ignoring the community a lot, here.

Namely, three of the most important (in my opinion) problems weren't fixed.

Comments STILL take a huge ton of space

Markdown is STILL lost when editing, even though it's been reported three weeks ago and is a massive problem. (EDIT: finally fixed, an astounding 22 days after being reported!)

The comment entry form is STILL above comments instead of below, which is made worse by the introduction of replies:

This is the bottom of the comment question and there are 8 more comments above, and considering how much space they take, this makes the comment second take approximately two screens.

Let's say I, a new user, want to post a new comment, not replying specifically to anyone, just wanting to ask OP for clarification. What do you think I will do?

A. Scroll up to find the "Add a comment" form because I remember it was there, and as a new user, I made sure to carefully read how comments work and am not going to assume they work the same way as on other popular websites

B. Just click the nearest "Reply" button

I'll let you guess which one is the most likely.

It's been 24 days since the initial post, and almost none of the feedback has been addressed. Only three (1, 2, 3a/3b) bugs have been fixed (some of them, silently), and only so because they essentially prevented the experiment from working.

This is a major problem. You can't just move on with the second step of the experiment in these conditions and expect positive feedback.

bug status-review

Replying with a long comment truncates the comment.

When replying to a comment, behind the scenes the system appears to prepend @target-username to the comment. If the comment is near the maximum allowable length then adding @target-username to the start takes it over maximum length and the comment is silently truncated to the maximum length.

The Comment UI needs to be updated to set the maximum allowable comment length in replies to be the maximum allowable comment length minus the length of the username and surrounding @ and spaces. (Or to generate an error message rather than silently truncating comments without any warning.)

bug

@replying incorrectly replaces spaces with dashes instead of removing them.

When replying to someone with the old reply system, the suggested reply @ appeared as follows:

Spaces are removed and the case is preserved.

This is no longer the case:

Casing isn't preserved (which is no big deal, since it is a ["case-insensitive match"](https://meta.stackexchange.com/a/43020/1723738, although it does look bad), but most importantly, spaces are now replaced with dashes.

Unless the matching key was changed, dashes are important and do count as username characters! "Single quotes, dots, dashes and underscores should not be removed.", implying none should be added either if there aren't in the user's display name!

This could create conflicts (if a user has username A person and one has the username A-person, trying to reply to A person might actually reply to A-person), and prevent users from receiving notifications altogether if the matching key wasn't changed accordingly.

If this isn't a bug and that everything was silently made to work properly with this change, why was it done without editing the username matching key post and the FAQ?

Even though this is an experiment, having a note warning about it is important.

And even then, why make this change?

The existing convention has been there for 15 years, such a baseless change is only going to create confusion.

I find the new comments quite hard to read when there isn't a reply, but just a list of several one-line comments. It's like double line spacing in Microsoft Word, except the space is filled with white noise rather than being empty.

Also, when there is only 1 single line comment, it comes across like the comment is a description of the comment box (like a footnote on an image)

Deleted posts

Since you specify that you “will be monitoring this post for feedback till June 19th, 2025”, it's quite unclear to me what is going on and what my answer may achieve, but:

1. While this deleted question explains “Comments disabled on deleted / locked posts / reviews”, on Stack Overflow, with that experiment, if I want to comment on this deleted answer, I am allowed to type a brilliant comment, until I click Comment and get "Cannot add comments to this post; it may be locked, deleted, or frozen". (I also got "Are you sure you want to add another answer?" once when trying at the top level.)
2. Still, this is a game-changer and the effort is really appreciated