In a social application focusing on a niche community where the level of comment quality matters, is it a good idea to enforce a minimum comment length?

For example, see this set of comments on a photograph:

enter image description here

You get the usual litany of responses like "Very nice," "Excellent," "Beautiful," and "Nice shot." All of these, of course, are super helpful, and could never have been expressed by simply clicking the like button. </sarcasm>

So does it make sense to set a bar? Be the anti-Twitter, so to speak?

Of course, there are ways to judge how valuable a comment was after the fact (voting systems), but there's no first filter there.

  • 8
    "For sale, baby shoes, never worn." That's an entire story by Hemingway. Commented Nov 2, 2012 at 8:00
  • 2
    @TylerLangan And it's longer than StackExchange's 15-character minimum limit, while the examples in the question are not. ;)
    – Izkata
    Commented Nov 2, 2012 at 15:17
  • insightful ***********15chars
    – badp
    Commented Nov 2, 2012 at 19:15
  • No - (Which already is an impossible answer here, granted this would be downvoted, so the real answer is "it depends" - look at the data you have or better yet encourage the type of comment you want by e.g. hiding stuff that is "unwanted") Commented Nov 5, 2012 at 17:56
  • 2
    I view inane comments in the same light as spam and believe it should be treated as such xkcd.com/810
    – Will
    Commented Nov 7, 2012 at 19:32

10 Answers 10


To me, this is all about alternatives, providing the "value menu" of things most people would want to say in a tiny comment, in one click.

enter image description here

Provided you have made the alternatives, e.g. "click the +1/awesome/like button!" discoverable and easy, I favor a blocking message like:

We prefer that comments be longer than 15 characters so they add substantively to the discussion. Click the "like" button if you just want to say "nice shot!"

You'd need to look closely at the pattern of comments to make sure you've provided the right one-click actions for the particular emotions they want to express, though. You might look at Buzzfeed, which has a ... lot ... of actions.

enter image description here That feels like way too many to me, but the only way you will know is to look at the data of what your users are actually doing.

  • Right on, Jeff. I'd also seen Chill allow a lot of different reactions awhile back, but they've since removed that option. I'm guessing hardly anyone used them.
    – Josh Smith
    Commented Nov 5, 2012 at 21:46
  • 1
    @josh you should think about whether the motivation is to provide feedback or to "sign" someone else's photo with your avatar to indicate support. Perhaps showing the avatar of all people who "like"d something is the way to get that feeling. Commented Nov 6, 2012 at 22:54
  • @JeffAtwood I do like that design technique, a la Quora. Have you seen it done better elsewhere?
    – Josh Smith
    Commented Nov 7, 2012 at 2:07

Well...is it a problem? I forget where I heard this, but there's a story about how everyone assumes those "no dogs" signs are just put up in stores just because they've always been there, it's convention. But really, those signs get put up because someone brought a dog, and it caused problems. To avoid further problems, they banned dogs. Now, maybe they didn't have a dog come into their store, but they had prior knowledge which led them to believe "if we allow dogs here it's going to cause more problems than it solves".

So how do you know when to implement restrictions like this? Look at your comments. Analyze your current (or eventual) comment base; how many are under certain reasonable thresholds? How many are under 50 characters? Under 10? Are those comments worth keeping around? Are they worth restricting?

Generally any barrier to user action should be well justified: Are they going to cost themselves (or you) money if they do this? Are they going to annoy themselves or others if they do this? Preventing people from doing something they wanted to do will annoy them; you have to balance this against restricting users from doing things that are actually destructive.

As a real life example of comment length restrictions, Stack Exchange has a pretty short minimum comment length; 15 characters. IMO this is probably to avoid comments consisting only of "thanks"/"+1" or otherwise completely devoid of content. That's not all that restrictive, and it's possible (but I'm not sure) it was based on real data; we do get junk comments, and users get stuck reading them, and moderators get stuck deleting them.


Have you considered offering a recommended limit? For instance, if a comment is less than say, 15 characters, upon submitting the comment the user is presented with an alert suggesting that they elaborate on their comment. This will make the user consider the value of their comment, and will hopefully trigger the action of adding more substance.

Always give the user the option to simply post the comment, even if under the suggested value.

Ignore the wording, but here's a quick mockup.

enter image description here

You could take this further by including the option to "Like" on Facebook etc or trigger a single word action as others have suggested.

  • 2
    I like that. Maybe auto-close the popup (and post the comment) after a few seconds (count down), because some users might change tab as soon as they hit the submit button (and they'd never see the question anyway in the next minutes, so they are probably not that interested in elaborating).
    – unor
    Commented Nov 3, 2012 at 12:24
  • I might like this option more. Less friction is better, IMHO.
    – Josh Smith
    Commented Nov 7, 2012 at 7:52

I think you should consider the ability to rate the individual comment again, in a similar style to the thumbs up/down buttons on YouTube. You could then have a top comments section which I'm sure would highlight comment that are limitlessly more thoughtful than simply "Nice one!!".

Further to this I find minimum constraints quite annoying wherever they are applied. Sometimes I'm not feeling creative enough to give a great comment, but I would like the author to receive some props for the great work they've done.

There will always be users that will comment thoughtfully. There will always be users who won't.

  • 3
    Your closing line sums it up really. You can be thoughtful in one line, and you can be thoughtful in 1,000. But the reverse means you can write 1 line of garbage just as you can do in 1,000. Length isn't always a measure of quality. (as my wife often tells me)
    – JonW
    Commented Nov 2, 2012 at 12:09

As in many of UX questions, the answer is it depends. It depends on several factors such as your sites' business goals, the users preference. If you're after "lengthier comments" - then go ahead - restrict a minimum lenght. But be aware of that it doesn't mean you'll get "quality comments" - which I read between lines is the real issue here - not length.

So how do we get quality comments to our forum? A question asked by every Stakeholder/Web Designer/Project Manager/CIO since the beginning of the Web. There are a few must haves such as only allow comments by logged in users. Another is some kind of moderation by an employee or a community. Leaving comments "free and open" can have devastating consequences.

But decide first what your objectives are - then ask for how to reach your goal.


It goes down to your strategy. Do you want users to user engagement? or Do you want quality user engagement?

Good example is Facebook like button. Simplest way for a user to engage with any content. And there is still a comment field for users to comment. This way users who want to say "nice" will just like it. If someone wants to comment you still can.

By setting a bar of minimum comment length you are loosing all those users who likes a photo. Do you want that? Well if you want to loose them that is a part of your strategy.


Rather than use technology to restrict user behavior (and thus preventing amazing yet short posts like the Hemingway story), you can implement a commenting guide. Its success would depend on the type of site and your users. Generally if it were something like flickr, nobody would read a commenting guide because the majority of user do not think of it as first and foremost a discussion forum. Reddit and Gawker have had more success with comment style guides (although not as much success as some would want) but they are sites that users visit specifically for the comments.

I know that using the quality of comments on Reddit as an example will raise some eyebrows, but the site is a perfect example of how to encourage or discourage quality comments. Some of their subreddits have horribly low standards for comments. Some have amazing comments. What are these great subreddits doing differently? Usually it's a combination of moderation, attracting the right audience, and emphasizing the importance of Redditquette (the commenting guide) to their culture, and allowing certain users to be distinguished as quality commenters. See /r/AskScience for an example.


In relation to your example, I think it's necessary to consider the question:

Why did the user feel the need to commment vs clicking a "Like" button

Is it because:

  1. They didn't see the "Like" button?
  2. They don't want to hide behind the anonymity of a like (or the opposite)?

If it's 1. then your commenting system could, of course, prompt the user to like rather than leave a short comment as a training exercise to teach the user about alternative functionality. You could identify these comments (as noise) by looking for common short phrases like "Nice <insert thing here>", "Your <insert thing here> rocks", or maybe just the number of exclamation marks ;-)

If it's 2. then what's the motivation for it?

Is it because

  1. The user wants to be identified as a shameless attention seeker?
  2. The user is hoping to engender reciprocal comments that they might not otherwise receive because they are hidden behind a number?
  3. The user genuinely wants to show their appreciation in a non-anonymous way?
  4. The user has something interesting to contribute to the discussion

1 - 3 are really noise. They can swamp 4, which is where the real value lies. Allowing lots of short comments risks increasing your signal-to-noise ratio and drowning out the comments which add value. Would a comment as brilliant as Hemingway's short story be noticed in a flood of 10000 tweets? I'd like to think it would, but I'm pretty sure it would get buried.

However, that raises another question; which is how do you establish worth? Length isn't always a good sign of quality (ahem), and brevity will sometimes make an effective point that 1000 words can never achieve. On the other hand, brevity can also be the sign of a lack of thought or noise.

Length alone is clearly not the deciding factor, but it's likely that there is a good correlation betweeen increased noise and overall length of comment. To reduce this noise, a cap is introduced, and, of course, one of the side effects is to also bar quality short comments.

It is unlikely, though, that you'll get something earth-shattering in less than, say, 15 characters. On the other hand, you'll get rid of:

  • Cool Picture!
  • Awesome Pic!
  • Great Picture!
  • Great!!!!!!!! (Personally, I think screening for multiple punctuation marks is a great idea ;-)

I like your picture! however, would pass in this instance, but is also noise. You could, then, also screen for these noisy comments, but that's a science in and of itself.

Although voting on a comment can potentially solve these problems (as you'd hope that quality items would get more votes than non-quality items) the number of times I've seen depressingly pointless comments reach the "top" of the You Tube charts often amazes me.

Popularity isn't necessarily related to awesomeness.

To summarize:

Having a comment cap can be an effective way of reducing noise, but also runs the risk of barring quality short comments. However, if the user is creative anough to come up with a great short comment, they'll certainly overcome a small character limit to make the same point.


Instead of enforcing a minimum requirement you could just encourage users to go beyond a certain length (e.g. 15 characters). Similar to the current StackExchange comments you could have a dynamic progress indicator as users type but rather the 'limit' could be soft and in a large-ish number than turns from red to green or perhaps a frown that turns upside down.

Users would still be able to post short comments if they wanted but may be encouraged to add a follow-up as well. (e.g. Awesome!!!!1 -> Awesome! How did you avoid lens flare from that angle?) If you're just trying to slow the deluge of insignificant comments this might be a good place to start without chilling comments too much.


Moderating/constraining comments may be a good idea for readable discussions. However, in this case your </sarcasm> could be replaced with <opportunity>. If your users are not clicking on like, you should ask why before you introduce a rule. Maybe it's because they are individuals, and individuals seek to express themselves in unique ways-words, even if the semantic bottom line is similar. Maybe people don't like to get pigeonholed into a standardized 'emotion' that loses its authenticity at scale. If I were you, I would reframe the problem as an opportunity: how can you facilitate genuine forms of expression that characterize and capture the richness in your community?

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