I've noticed a message in mathoverflow's place for comments saying that '+1' or 'thanks' comments are not appropriate. I don't agree with the second kind of comment being inappropriate. I think it's appropriate in many cases, e.g. if we accept an answer but there are others which are equally useful, if we want to express our appreciation on an answer to a question we haven't made, etc. Could this message be modified?
I think that this is part of the network-wide changes. We can't control them, and they are applied uniformly across the SE network.
The thing is that on sites like StackOverflow, and on many other sites in the network, the community norms and etiquette can be very very very very different from the ones here (and on math.SE, for that matter).
It's good to remember that, when you see a feature like that. And then continue to ignore it.
I would like to suggest a different or more nuanced reading of the advice. Namely, the advice is to avoid comments that only contain this.
I agree it can be appropriate and nice if a questioner thanks the other (or all people) that provided answers beyond an accept and an upvote. Or, also other communication in the comments.
However, I also think that it can be still nicer if the comment is not only a quick "Thanks!" (plus something to get over the character limit) but actually says something specific or personal, for instance in the situation described it is not unlikely one could highlight a point that one specifically appreciated about this one answer.
Or, put differently, a 'thanks' comment can be appropriate but I think in most cases a comment containing not only 'thanks' but also something in addition can be even more appropriate.
Still put differently and somewhat jokingly, if somebody often writes comments containing only 'thanks' they do not put enough effort into expressing their gratitude.
I should also add that it is my understanding that this reading of the advice is not an absurd one (relative to its intent). Also comments should add some information, a comment that thanks in a specific and somewhat detailed way does, only "thanks" does not.
I think the reason why SE discourages such comments becomes clear if you look at how SE views comments.
AFAIU, from SE's perspective the purpose of comments is not having conversation. A good comparison might be Wikipedia articles and their talk pages. Comments which are not providing useful relevant information or suggest improvements to the post should not be posted (and can be removed as obsolete or too chatty). Only the content which is relevant and useful for later readers should be kept.
Just to clarify: I am not saying we should follow this on MO, I simply explaining SE's perspective AFAIU.
What are comments?
Comments are temporary "Post-It" notes left on a question or answer.
When should I comment?
You should submit a comment if you want to:
- Request clarification from the author;
- Leave constructive criticism that guides the author in improving the post;
- Add relevant but minor or transient information to a post (e.g. a link to a related question, or an alert to the author that the question has been updated).
When shouldn't I comment?
Comments are not recommended for any of the following:
- Suggesting corrections that don't fundamentally change the meaning of the post; instead, make or suggest an edit;
- Answering a question or providing an alternate solution to an existing answer; instead, post an actual answer (or edit to expand an existing one);
- Compliments which do not add new information ("+1, great answer!"); instead, up-vote it and pay it forward;
- Criticisms which do not add anything constructive ("-1, see previous comments you scallywag!"); instead, down-vote (and provide or up-vote a better answer if appropriate);
- Secondary discussion or debating a controversial point; please use chat instead;
- Discussion of community behavior or site policies; please use meta instead.
Comments can become a bit unwieldy; they can attract quite a bit of noise that tasks moderators to disposing of it. There are two kinds of comments that we can consider valuable to future visitors, and our sites are all about helping future visitors equally well as the person that asked a question:
- Corrections and clarification that should be moved into a post
- Related short conversations that illustrate someone's process of grasping the knowledge an answer shared.
Comments like thanks!, this was awesome!, Wow, you nailed this! can sometimes be harmful because they fragment or even hide the types of comments that someone might actually find of value. This could mean that a point raised and addressed in comments never makes its way into the actual post where it should be, or valuable short discussions become fragmented and obscure.
Remember, everyone loves to up-vote a thank you comment to increase its sentiment and they can quickly bury hints that expanding comments might lead to something worthwhile.
It became enough of a problem that we added the hint right in the text input box, after so many moderators across the network expressed their frustration with having to clean up comments.
As noted by several others, every community on Stack Exchange is its own entity. As long as each community has struck a balance with the moderators that serve it, we're generally happy. As a general rule, if anything is consistently obscuring valuable information, we pay attention and try to make changes to keep that from happening.
It's not a major problem on Math Overflow, but something to watch as your scale continues to grow.
Finally, if you see oddly specific help such as this, it's generally indicative of us applying a stop gap solution while we evaluate a more holistic solution to a problem, which is the case here.