Currently it requires a reputation of 50 points or more to post comments to other users' posts. This creates some problems for new users :

  1. Instead of commenting they are tempted to post "answers" which are nothing more than comments. These have to be reviewed and/or flagged for deletion.

  2. Instead of being able to ask for clarification of posted answers, they post a duplicate question explaining that they did not understand the answers already posted. The new question is flagged for review as a duplicate. For example : How can the Fermi level be in between the band-gaps?

My concern is not about the fairness of this policy, as is the case in Why do you need 50 reputation to comment on other posts? My concern is about the practicality of it. Are the difficulties which it creates greater than the benefits of the policy?

Comments are temporary, subject to deletion by moderators, and of less importance than answers. It seems to me inconsistent that it requires more rep to post comments than answers.

Should this policy be changed? Should the restriction on posting comments be removed?

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    $\begingroup$ I'm almost certain that this is a change that (if it happens) will not be made at the individual SE level, but should be requested at Meta Stack Exchange to begin with. $\endgroup$ – ACuriousMind Jan 25 '17 at 0:55
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    $\begingroup$ Yes, it helps prevent spam. $\endgroup$ – Kyle Kanos Jan 25 '17 at 1:55
  • $\begingroup$ How can you weigh these disadvantages against the advantages when the latter are, by definition, invisible? How can you measure the amount of spam that we don't get, because spammers know that commenting on SE is impractical? $\endgroup$ – Emilio Pisanty Jan 25 '17 at 12:53
  • $\begingroup$ @EmilioPisanty : Yes exactly. Where is the evidence that the policy does actually prevent a flood of spam? The alternative of posting spam questions and answers is still available, so why isn't there a flood of those? $\endgroup$ – sammy gerbil Jan 25 '17 at 13:04
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    $\begingroup$ @sammygerbil Who says there isn't? There's a fair amount of spam but it is easy to manage because there are review queues dedicated to managing it. (Once you reach 10k you'll be able to monitor recent deletions and maybe you can actually present data that it's not as meaningful.) Unless you're proposing an equivalent review queue for first-user comments, and effective ways to moderate them, though, none of those defense mechanisms apply. $\endgroup$ – Emilio Pisanty Jan 25 '17 at 13:09
  • $\begingroup$ @EmilioPisanty : In physics the onus is on those making extraordinary claims to provide the proof. Doesn't this site operate on the same principle? Or is fear and suspicion how we make decisions here?... I don't think a review queue is needed. Ordinary users can flag spam comments for deletion. $\endgroup$ – sammy gerbil Jan 25 '17 at 13:19
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    $\begingroup$ @sammygerbil Precisely, and it's you that's making the grandiose claims of harmful rules, so it's on you to provide the proof. In any case, 'ordinary users can flag spam comments for deletion' is hopelessly naive, since typically only the OP would get notified and we have a large tail of posts whose owners haven't been seen in a year or more. I don't fancy having to individually flag 50,000+ posts whose users haven't been seen in over six months. $\endgroup$ – Emilio Pisanty Jan 25 '17 at 15:37
  • $\begingroup$ @EmilioPisanty : I am not making grandiose claims. I don't claim it is a big problem, only that the disadvantages might outweigh the actual (not imagined) benefits. ... I am not suggesting that anyone searches for and vets 50k historic comments, only pointing out that ordinary users can (and do) flag objectionable comments as and when they find them. $\endgroup$ – sammy gerbil Jan 25 '17 at 17:09
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    $\begingroup$ I disagree, but you're obviously not going to change your mind, so I'm out. I don't think you've shown any real case of meaningful disadvantages for the current setup, nor any credible way to mitigate the real risks carried by the change you propose. You also misunderstood the 50k figure: those are 50k posts that are susceptible to getting spam comments at any given time and which would need to be monitored regularly - and which would be visible to a large population of site non-signed-up visitors that would have no possibility or incentive to clean them up. $\endgroup$ – Emilio Pisanty Jan 25 '17 at 17:25
  • $\begingroup$ @EmilioPisanty : As far as I'm aware, nobody is monitoring comments by users with sufficient rep to comment. Anyone determined to post spam comments can easily amass a rep of 50 and then do so without being monitored. ... Actually I have already changed my mind and accept that the change to unrestricted commenting is not worth the effort. $\endgroup$ – sammy gerbil Jan 25 '17 at 17:56
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    $\begingroup$ I don't think you understand how spam defenses work. Any account(/IP address/computer/identifiable source) that posts more than X comments in a given time is marked as suspect, so spammers need to spread the load over many different origins. They can easily gain 50 rep to comment, but they cannot easily gain 50 rep per account for the hundreds of accounts they'd need to stay under the radar and still get meaningful hit rates. Stack Exchange has been doing this for a while (and simultaneously being part of the network makes us a more valuable target). Why don't you talk to the team about this? $\endgroup$ – Emilio Pisanty Jan 25 '17 at 18:00

The structure of Stack Exchange site privileges is partly gamification to get you hooked, but it is also about controlling both malicious and negligent attacks on the system.

Comments are not subject to downvotes and are designed to be transient so there is no penalty to a user when a comment is deleted. Which means that they represent a low risk channel for users to be obnoxious. Of course, established users risk being suspended for that behavior, but if we let users access the comment system fully without some kind of vetting then a malicious user could send the mods on a merry game of whack-a-mole as they post nasty comments, get cut off, re-appear from another IP and go 'round and 'round.

The relatively minor barrier of a low rep threshold represents a short time when a productive member of the community can't play a full role, but slows the hypothetical comment spammer considerably.

You might still ask if 50 is the right threshold (and I think it is set lower on beta sites), but I rather doubt anyone is going to get very worked up about it.


I think that new askers are more likely to get their questions answered, and new answerers are more likely to have their answers actually help people, if they post questions and answers rather than comments. Here are some reasons why.

  1. Instead of commenting they are tempted to post "answers" which are nothing more than comments. These have to be reviewed and/or flagged for deletion.

While that's true, the mechanisms for alerting reviewers and other users to new answers are much more robust than for comments. A not-useful comment, for instance, can't be downvoted --- only flagged for moderator attention. It's much more efficient to have the entire community empowered to evaluate low-effort contributions from new or low-rep users than to ask the moderators to shoulder that entire burden.

I personally think that asking people to write paragraph-complexity answers and questions that five or ten other users find voteworthy to be a pretty low bar for the privilege of leaving a sentence-complexity comment.

Moderators can (and sometimes do) convert brief non-answers into comments, but I mostly encourage people to meet the participation threshold and come back.

  1. Instead of being able to ask for clarification of posted answers, they post a duplicate question explaining that they did not understand the answers already posted. The new question is flagged for review as a duplicate.

Consider the alternatives here.

  1. Comment from a new user to an old question: "I don't understand any of the answers here, please explain more." Depending on the age of the question, its asker may never get notified about the comment. Commenting doesn't bump a question to the front page, so other users don't notice the new comment either. New user does not get help. The end.

  2. Duplicate question from a new user: "I don't understand the answers over there, please explain more." Question appears on the front page and the in the First Posts Review Queue, where many people see it. Those people will vote and ask clarifying questions in the comments, possibly while the new user is still hanging around. Maybe the question gets closed, and maybe it gets answered, and maybe both.

  3. "Duplicate" question from new user: "I don't understand the answers over there for reasons A, B, C." That's potentially a good new question.

The thing is that there's a path from (2) to (3), via editing of the new question, but the path from (1) to (3) is much more tortuous.

(Furthermore, as ACuriousMind says in a comment, I'm pretty sure that individual SE sites don't have the ability to muck around with the privilege hierarchy. So this isn't something that could be implemented only on Physics --- you'd have to drag the entire network along.)


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