Is there any good reason to enforce a maximum length for comments?

Question

This is sort of the antithesis to this question.

A lot of websites - including the Stack Exchanges - will only allow commenting up to a certain length. It tends to sit between 300 and 600 characters from what I've seen, but I've been wondering why enforcing this type of limitation is so common.

We can assume that physical storage space available to comments is as-good-as unlimited (if a web server is able to store complex articles/questions, images and everything else required by a website, then the total amount of space used by text comments is surely somewhat negligible), so I doubt it's that.

Secondly, it doesn't really limit users to posting comments within the size limitation. It just creates a hurdle to jump. Typically, when a user hits it, you tend to see them just do this:

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris ac orci justo. Aliquam volutpat metus quam, sit amet vehicula lacus dignissim sed. Cras eget euismod augue. Praesent ut felis libero. In fringilla augue vel nibh suscipit hendrerit. Proin auctor at erat in dignissim ... – LatinGuy99 Mar 25 '14 at 12:30

(cont) ... Vestibulum iaculis laoreet elementum. Nunc gravida placerat orci, eu semper lacus blandit id. Nullam varius, turpis ac laoreet pharetra, odio nunc pellentesque ligula, non convallis diam enim ultricies purus. – LatinGuy99 Mar 25 '14 at 12:31

This seems like bad UX for a few reasons:

• As stated above, it doesn't actually limit users in any meaningful way, unless actively moderated.
• Refactoring a comment to fit within the limit is often frustrating.
• Multiple-part comments are harder to read.
• On busy comment threads, causes a rush-to-finish to get the second 'part' of the comment posted before somebody else drops a comment inbetween.
• Particularly tight limitations can encourage txt spk 2 manifst (see Twitter), which is often not desired when attempting to attract and maintain a "professional" community.

I can only see two real advantages to the limitation:

• It prevents users from posting a 'wall of text', but there are better ways around this that don't push fixing the problem onto the user (for example, long comments could be folded with a link to expand the full text).
• It enforces the idea that comments are typically intended to be short, not an essay. However, the vast majority of users are unlikely to want to post enormous comments anyway. It seems unnecessary to restrict the few that do.

So are there any real advantages to restricting comment lengths?

Answer 1

It is not bad UX, it is good UX exactly for the reasons you listed.

The site has some business reason to not want to have long comments. It doesn't matter what their reason is. They don't want them, and they know that they can't make the system so watertight so the users won't ever do it.

So what they do is a very good UX. They 1) make it clear to the user that what they are doing is not what they are supposed to do. The user still can work around the technical limitation, sure, but he is subtly informed that he is skirting the rules and 2) make it unpleasant for the users to deal with posting and reading too long comments.

About 1) If the user wasn't realizing that his comment is getting so long, hitting the max length is a good way to jostle him from his writer's flow and make him reconsider. If he notices it and decides to post a superlong split comment anyway, he is at least made aware that he is not supposed to be doing it. I have first-hand experience that it works :)

About 2) Good user experience doesn't mean that everything on your site should be a breeze for your user. It means that the path he should be taking for the site to achieve its purpose (which is hopefully serving the long-term goals of the users even when it is in conflict with their short-term ones) is made obvious and easy. Putting hurdles onto the paths he shouldn't be taking, for whatever reason, is a big part of good UX.

Answer 2

• Many, Many more people read a comment then write it.

• It costs more to read a comment if it is longer.

• It takes someone longer to condense their thoughts into a short space.

So by having short comments we put the cost on the writer, rather than every reader.

Answer 3

Wall O' Text - It's a wall!

Typically, comments are ordered chronologically, top to bottom, with latest at the bottom (Facebook comments, Twitter conversations, StackExchange comments etc.). Now if a wall of text exists, like 10-20 scrolls long, who would want to continue down and find the rest? We're not talking about the UX of the writer, we're talking about the UX of the readers.

Comments, they are what they are

Comments are like opinions, short somethings about something. Character limits enforce the fact that you are writing a comment, not a post. If you're about to explain a reply worth 20 pages, it would be wise to place it in a separate article, and just link it to the article you are going to comment on. Again, we are thinking of the UX for the readers, not the writer.

UX for the reader???

How much time does a commenter spend writing a comment? Does he even go back to the page he commented? Compare this to the millions of users who are looking for a post, reading the comments for further info. Why waste time and energy on the commenter who never goes back to his own comment, when you can improve the UX for the readers who come in by the millions.

• As far as I know Facebook imposes a long limit for comments (I think they still have). But notice that long comments get clipped when you read, and only display when you click "Continue" or "Read More"? It's for the reader's UX.

• StackExchange, aside from collapsing comments, impose a comment voting system. High-scoring comments hidden under the collapsed sections get bumped-out from being hidden. This also means nonsense comments, or lesser-valued comments get hidden.

When will I reach the bottom?

Some sites offer a site map (a bunch of links to the entire website) at the bottom of the page, like the one you find here in StackExchange. It has been a design pattern, and a convention in a sense that, along with the top nav bar, if you get lost, you just scroll to the very top or the very bottom. If you have this very long wall-o-text, when will you reach the bottom and find the nearest teleporter?