I left a brief question in a comment, and got a helpful reply, also in a comment. Then I wanted to leave a reply that said "Thank you.", but the comment system will not accept a comment of fewer than 15 characters. I inferred from this that the community does not want such comments posted. Is this correct? If so, what might I do instead to express gratitude?

Addendum: I was hoping to understand the feelings of the se.math community about this matter. But the majority of the comments and answers so far have been from people who are only peripherally members of that community. That helps me understand what these people think the etiquette should be, or what it is like elsewhere, or what the site implementers expected it to be. But it does not answer my question, which is what the etiquette actually is. I would not want to deny these people the chance to express their opinions. But I think it would be more useful to myself and to the se.math community to find out what other se.math community members think about the issue.

• Just say thanks and add something like ${}{}{}{}{}$ which is invisible and takes up space. – Mariano Suárez-Álvarez May 22 '12 at 19:00
• Thanks! I did not want to skirt the ban on short comments without checking first that it was okay. – MJD May 22 '12 at 19:01
• – Isaac May 22 '12 at 19:29
• The attitude evinced in the answers there (“‘Thanks’ is noise”) is exactly why I did not want to evade the limit. Do people on se.math feel the same way? – MJD May 22 '12 at 19:34
• Hooray, I'm helpful. Sock it to everyone who ever claimed otherwise! :-) – Asaf Karagila May 22 '12 at 20:26
• test ${}{}{}{}{}$ – user2468 May 22 '12 at 20:49
• Why not just write, "Thank you, [insert screen name here], for your helpful reply"? Avoids the character counter and avoids any ambiguity as to whom exactly it is that you are thanking. – Gerry Myerson May 22 '12 at 23:43
• "Thank you very much" works. – user1729 May 23 '12 at 9:43
• @Gerry Are you suggesting that "Thank you, [insert screen name here], for your helpful reply" is preferable to "Thank you, ${}{}{}{}$"? If so, can you explain why? I do not see it. – MJD May 23 '12 at 13:44
• @Mark: Addressing the person you're thanking by name might be preferable when there are other commenters in the thread (not always applicable). It could also give the "thanks" a more personal feeling. – Jonas Meyer May 23 '12 at 14:02
• @Jonas Certainly, but I think in this case it would have seemed silly, and I would have felt just as uncomfortable about appending Asaf's account name just to get around the 15-character limit as I would have felt appending anything else for the same reason. – MJD May 23 '12 at 14:31
• Mark, I think that your addendum is a little bit insulting and you should consider either toning it down or removing it altogether. – Asaf Karagila May 23 '12 at 21:09
• Well, nothing specific comes to mind (it is 2am after all) but it seems as though you request from the SE admins to stop participating in the conversation. You need to remember that this is their platform and their servers. They can and will do what they think is right, including giving their opinion. You should try and encourage math.SE users to write answers instead. Positivity just sounds a bit better, I guess. – Asaf Karagila May 23 '12 at 23:04
• In the context of the particular comment thread to which Mark is referring, I have no preference for any particular way of leaving a comment to thank Asaf. I have certainly used the {} trick myself. – Gerry Myerson May 24 '12 at 1:56
• If you really want to thank someone, do it properly :) – Alexei Averchenko Jun 17 '12 at 12:01

I inferred from this that the community does not want such comments posted.

Well, it's a bit more than that.

The design of Stack Exchange grew out of a frustration with traditional forum / message-board / newsgroup discussions.

Not because they don't work to solve problems, but because extracting the results is so tedious. Rarely does anyone go back and summarize a back-and-forth discussion; future readers must (if they can find it at all), trudge through the entire conversation, gleaning tidbits of useful information like so many wild strawberries scattered along a mountain trail. Which is quite a relaxing activity, provided you're not very hungry.

Well, so this desire to build a tool for organizing information in structured Question + Answer format ran into a bit of a hiccup early on: sometimes you need a bit of discussion. To clarify what's being asked, or hammer out the finer points of an answer. So comments were added.

...and immediately blew up. Wasn't long before there were posts with dozens, scores, even hundreds of comments attached, tangential discussions and critical critiques mixed together like a strawberry-and-olive milkshake. This wasn't working.

So a few changes grew up over time, with the aim of suppressing non-essential commentary:

1. Lengthy comment threads get hidden. Only the first - or most-upvoted - comments get displayed by default. This is why voting on a helpful comment is important, in particular if you can't edit it into the post in some form: an up-voted comment will rise to the top of the pile where it can be quickly accessed by future readers.

2. Very short comments get blocked. "Thanks!" may seem very friendly and personal, all there by itself. But once they start piling up, they're just more scrolling. Of course, this is perpetually controversial, since it's always other people's comments that are annoying or noisy. When I write "Thanks!", it's a masterpiece of modern literature in one word.

3. Flags for noise. Desiring to keep those most relevant comments quickly accessible, some folks started looking to clean up comments that had served their purpose. So the flagging system for comments was expanded to include off-topic, obsolete and "too chatty" options. Note that comment flags - unlike normal flags - don't impose any penalty, leave the flagger anonymous (even to moderators), and don't leave any sort of negative mark on the profile of the comments' author; they're just a quick way of getting non-essential comments cleaned up.

So then what can you do to express gratitude?

Well, you can cheat - either by padding out the comment in a way the system doesn't detect, or just making it more verbose; "My utmost gratitude to you good sir for your excellent response!"

But you're probably here to trade knowledge rather than social niceties. So in a sense the most sincere "thanks!" for knowledge gained is giving a little back... Whether that's telling the person you're thanking why his words helped you, or passing the knowledge gained on to someone else - and crediting its source.

• I have flagged as not constructive few comments like this: very nice. thanks a lot – user165145 (see the second comment below the answer), but the mods obstinately declined my flags. Are you contradicting each other? (I've also asked them to explain me why keep such comments, and the flag was also declined without any explanation.) – user26857 Jul 21 '14 at 5:37
• @user26857: I think when it comes down to really deleting such comments... if it's just one courteous comment, we're not so nasty to remove it hahaha... (I'm not a moderator so I'm just guessing.) – user21820 Jul 21 '15 at 2:32

The SE-wide common way to say "Thank you" is to upvote the post, that's what that feature is meant for. While a single "Thank you" comment is nice, it can quickly get confusing if a dozen users add such thank you comments, and drown out comments that actually address the substance of the post.

But there's a different case that is very common, and that is thanking a user for the answer and confirming that the solution is working. While that can be achieved by marking the answer as accepted, I find it often the case that I can add some useful information in my comment, thanking the user and confirming how exactly the answer solved my problem at the same time. I always find it preferable to add some real content to such a comment, instead of just posting a thank you.

• Fabian, judging from the given context the comment was a follow-up question by a user which was not the one asking the original question. In such case there is really no harm in thanking the person which answered the follow up (especially since this follow might have been closed as a duplicate as it appeared on the site in one way or another). Disclaimer: I am not just saying that because I am involved in the topic, this is how I honestly feel about thank you comments. – Asaf Karagila May 22 '12 at 21:55
• @asaf there is harm to the untold numbers of readers of the question and answer, who now have to parse through interminable instances of "thanks!" text that add nothing substantive or constructive mathematically to the question or its answers... – Jeff Atwood May 23 '12 at 5:21
• Dear @Jeff, if everyone tried to make a phone call simultaneously, chaos would follow—that also never happens, and we could probably both list lots of other possible catastrophes which never occur in practice! While an interminable string of thank-comments would surely be problematic, a thank you comment adds something substantial and constructive: it is a nice thing to do. – Mariano Suárez-Álvarez May 23 '12 at 6:07
• @mariano platitudes are insufficient; I suggest being a bit nicer still and explaining specifically how the comment/answer was helpful. This will certainly be far more useful as feedback, both to the person you are responding to, and also to future readers, than any mere "thanks!". – Jeff Atwood May 23 '12 at 6:12
• Having been on the receiving end of such platitudes a few times, I can tell you it was quite sufficient to me, at least: it is enormously more satisfying to have a thank you from the asker of a question than a few anonymous upvotes and, even, than having the answer accepted. Humans are prone to such display of pointless platitutes, at least those whose company I value. – Mariano Suárez-Álvarez May 23 '12 at 6:19
• @Jeff: Have you even seen the specific comment in debate here, or are you talking about a general situation? You should be aware that sometimes there is really nothing more to add on a simple "thank you" message. – Asaf Karagila May 23 '12 at 6:48
• @mariano I urge people to aspire to greatness in all things, including thanking others by being specific about what was so helpful/useful to them. Oddly enough, while we've always given this advice at SE, there is an entire chapter in this amazing book that provides nearly identical advice. When you say "thanks!" or "great job!" or "you are so smart!" it does not indicate that you actually listened to the other person (whether child or adult), merely that generic one-size-fits-all feedback was given. – Jeff Atwood May 23 '12 at 7:21
• Well, that advice seemingly also does not fit all, either. I find it silly as it applies to the situation at hand. I do respect your decision to follow it, of course. – Mariano Suárez-Álvarez May 23 '12 at 7:29

Mariano Suárez-Alvarez, a moderator, says that it is okay to trick the character counter in this case by inserting some invisible text such as ${}{}{}{}{}$.

• I respectfully disagree; it is far better to leave a comment explaining specifically why the comment/answer was so useful to you rather than a generic "thanks!". If explaining seems like too much work, well, that is what the handy little upvote arrow next to every comment and post is for :) – Jeff Atwood May 23 '12 at 5:19
• @JeffAtwood We are humans and want to follow human social norms. It is a social norm to thank the person who has done something for us, and to do it personally. An upvote is insufficient as a way of conforming to this norm. – user23211 May 23 '12 at 8:45
• @ymar if you truly wish to thank someone, then do them the courtesy of taking the time to be specific and concrete about how they helped you. That is more effective and more meaningful than a mere "thanks." – Jeff Atwood May 23 '12 at 8:49
• @JeffAtwood No, of course it's not. It may be sometimes, but usually explaining how an answer helped me is a waste of time. When I ask a yes-no question, and someone answers it with a proof, it's enough for me to need to thank them. Yet explaining why I find the answer useful is pointless. I find it useful because it answers my question. – user23211 May 23 '12 at 8:52
• @ymar then use the upvote arrows; the virtual world need not be as cluttered and noisy as the physical world. It is not a copy, it is an improvement. I assure you that the sensation of seeing a number next to your content go up, based on peer input and review, is very satisfying. – Jeff Atwood May 23 '12 at 8:56
• @JeffAtwood I refuse to do this. It's against my needs. – user23211 May 23 '12 at 8:57
• @ymar cluttering the site with a lot of unspecific "thank you" content, particularly when the upvote arrows are there for precisely this purpose, is against the needs of most people who will ever read the content on the web pages we are creating. Questions are asked once, answered a few times, edited a few more, but read thousands, maybe even millions of times. We try to be considerate of the needs of the silent majority, who seek knowledge and learning above all else. – Jeff Atwood May 23 '12 at 9:02
• @Jeff, Mariano has already answered this in a comment. This has nothing to do with the practice. There is usually one thank you note under an answer -- from the asker. And that's as many as there should be. Whatever you views on this are, there is a personal relation between the asker and the answerer, created at the moment of posting the answer. This relation produces feelings such as personal gratitude, which need to be vented. – user23211 May 23 '12 at 9:14
• @Jeff: The "virtual world" is neither a copy nor an improvement on the physical world. It is part of our experience of the world, and in my experience upvote arrows are neither a copy nor an improvement on personal words of thanks. Nor are they necessarily worse; they are different, and serve a different purpose. Sometimes a more personal touch is appropriate. Whether upvote arrows are satisfying to me, ymar, etc., cannot be assured if they are not. Your point about clutter is understood, but at least on this site, thanks are used sparingly and don't seem to cause actual problems. – Jonas Meyer May 23 '12 at 14:09
• To add on the point of the above comments, @Jeff, it is fine that your experience from SO tells you that this is clutter which sorta clogs up the reader, but as we keep telling everyone which comes from other SE communities - this community is inherently different. We like CW stuff; we like thank you comments; we dislike necrobumps even if they do improve by a (very small) positive amount the post. This is our community and we run it as we see fit. As long as it's working, I don't see what the problem is. – Asaf Karagila May 23 '12 at 14:35
• @AsafKaragila: I think some care needs to be taken as to who the "we" is in your comment about what "we" do and do not like. My preferences are much more in line with Jeff's on most of those things—because I have seen the problems with them on SO, because I have read the discussions on meta.SO arguing both sides, and because I simply do not buy the argument (which may not be your argument here) that math.SE is for some obscure reason (other than because of some people's MO experience) unique among SE sites. – Isaac May 24 '12 at 3:55
• @Isaac, I do agree about the use of "we" which I may have overdid there. However this is not the first time such discussions run here, and there is a fairly same result to most - at least as I remember it - which is what I wrote. – Asaf Karagila May 24 '12 at 5:45
• I do not have anything against short thank you comments. But given how many simple ways there are to get above 15 char, and given the ways there are to "cheat" the system without MJ, I really think that use of MathJax here ought to be avoided. MathJax is for math, and math only. – quid Dec 5 '14 at 19:24