Q:

Can we do more than just delete rude comments?

Lately it feels like there's a growing perception that Stack Overflow is not a nice place. I still feel like it's the best place to ask programming questions on the Web, but apparently not everyone agrees.
Suggestion: Can users be sent an automatic warning with a reminder to Be Nice if a number of their comments are flagged as rude? (3 in a week? 5 in a month? Recommendations welcome.)
I know that a lot of these comments are deleted already (both automatically and by moderators), but lately that feels like just sweeping the problem under the rug. The comments continue to be made, so maybe we can do more to prevent them?
Some questions:

Is anything like this already in place?
Is there (anonymized) data regular users can access to see how big a problem this is?
Should this be escalated to a moderator flag after a number of warnings to the same user?

Update from the comments: A couple of people have suggested that letting people know when their comments are deleted would be a good intermediate step. It would probably be too noisy for every(?) comment, but could probably work if a certain threshold of comments were deleted for being rude in a short period. Just letting people know that rude comments will be deleted might be enough to decrease the number that are posted to begin with.

A:

The direct answer to your question is ...
Probably. And we should.
I'm going to meander a little bit here and throw out some observations, in no specific order, but hopefully they come together as something coherent.

We might not be as nice as we think we are, and that could be because we're in the middle of a generation gap. I noticed this when I expatriated from the US and came back almost 15 years later, the bar for "nice" in ordinary discourse had raised considerably. It moved from simply not saying mean things to more proactively considering the other person's feelings, or in other words, being more empathetic.

It's genuinely difficult to track 'rudeness' in the absence of deliberate insults. These tiny (aka 'micro') aggressions can appear in the form of someone simply assuming your gender, race or other parts of your identity, that you require oversimplification of your problem, or someone just pointing out everything negative about something you contributed without any mention of the positive. Alone, isolated, these things can be cast off as noise, but the sum of them over time can be pretty crushing.

And I think this is a pretty big one, it's hard to imply that you know more than someone else does without coming off as condescending; this is exacerbated by communicating without facial expressions, diction, inflection, etc.

Yeah, you still have some pretty blatantly rude and condescending stuff.

So there's two things that we need to do in order to get out ahead of this a bit more.
#1 - We have to do more about quality.
I can't go chiding people for losing their cool occasionally when they spend so much time in the salt mines we call review until I can say that we've made every reasonable stab that we can at helping people ask better questions through the means that we have that can influence every single programmer with a problem to solve - our software.
We're working on this now through a bunch of tests and UX research, a big part of it is doing a better job of setting people's expectations based on what they're about to submit, while doing a better job of getting likely duplicates in front of them.
There's also a big part of the new culture that says hey, just ask and save some time which we need to find a way to address. We're increasingly unique by insisting that people do their homework first as far as expectations that being 'on the webz' might set. More hurdles mean increasingly worse solutions here, it's an interesting problem.
#2 - We have to be more cognizant that people make everything work
We've done extremely well by establishing a very high bar for entry and refusing to lower our standards of quality. We absolutely, positively, without fail must keep those things.
At the same time, we need to look at how our software isn't doing a very good job of reminding people to value contributors as much as we do contributions, while also maintaining that it's all about the posts, not so much the people that write them. That doesn't have to be a contradiction, but it is a very deliberate and difficult balance to strike. We're doing a lot of research (which is soon to turn into sentiment analysis) right now of feedback that we're hearing in a variety of places. Probably the most important part right now is just listening and trying our best to not be obtuse.
So, what are we doing?
Pretty much what you're doing which is admitting that we have a problem and that it's scary, and that we need to do something smart about it. Sure, yes, there's going to be some short-term low hanging fruit where the most obvious incidents get handled more efficiently as we work to better understand the majority of it, which tends to be a lot more subtle.
At the end of the day I have to remember that we're a mirror, we're essentially a living example of how developers relate to one another with the added bonus of removing many social contracts that face-to-face communication imply. But, we're a mirror with a voice, and we need to use it more effectively to ensure the greatest possible majority of people feel reasonably safe and confident using our software.
There will be more about this from us as we dig further into it, but I really meant what I said - as long as we continue to owe our reviewers and most engaged users much needed bug fixes and tweaks, well, the blame is mostly on us when they start to sound kinda sick of it.
Fortunately, we can do a lot of this asynchronously, and research being done by a small working group is underway. We'll post back with more, and, well, sorry for the brain dump, I hope folks find something of interest and value in it.

A:

As meagar and others have mentioned, an automatic flag was added a couple of years ago for people who repeatedly have their comments deleted when flagged as "rude" or "not constructive". This has allowed us to identify patterns of rudeness that might have been missed, and to act on that.
However, in the time that this has been active I've observed that it doesn't quite cover the cases mentioned in my original feature request: extremely insulting comments deleted automatically by community flags and then hidden from moderators. To deal with extreme abusive users, we need to be able to take action immediately and prevent them from negatively impacting others.
The system is currently configured to automatically delete comments containing certain highly offensive words immediately when flagged by anyone in the community. I still think that moderators should receive a special flag on every instance of this, so that we don't have to wait for people to use custom flags to point out slurs or obscene insults or for enough of them to pile up to trigger an automatic flag.
Shog9 worries about the noise this would cause in his response to my original feature request, but that's because the one-flag deletion currently has a lot of other triggers ("what have you tried"-style comments, etc.). I propose setting up a subgroup of the automatic deletion trigger phrases for obscenities, slurs, and similarly abusive words and having this automatic flag trigger on only those. I think this would allow moderators to act on directly insulting behavior far earlier, causing it to impact fewer people.
Will that have a huge impact? Maybe not, but it will help out in a few areas. I believe that a much larger improvement in tone and signal to noise ratio in comments could be made with a better comment moderation system.
Questions and answers are currently subject to a lot of review when they come into the site, and a robust moderation system has built up around them. Comments, where you see most instances of rudeness and unconstructive behavior (as well as annoyances to higher-rep users and the occasional spam), have nowhere near as much review. They currently rely on people happening to come across bad comments, flagging them, and then having our small group of moderators review each one of them.
We need a better way of making incoming comments visible to the community so that problems are caught and acted on sooner, and in such a way that scales with what elected moderators can handle. Is that a community review queue for new comments on old posts, comments by new users, or all comments? I don't know, but I really think something is missing here.
Better comment review might also allow us to ease restrictions on posting comments in certain places, cutting back on a source of frustration for new users and reducing the number of non-answers posted to the site. That may indirectly help improve the perception of the site as hostile to new users, as well as the more significant benefits that will come with better comment moderation.

A:

What a great question! I'm not sure I have an answer other than: yes, yes we can and yes we absolutely should. It is my supposition that it is also not just a "growing perception" but rather an indisputable fact. If it makes us feel better to call it a "perception" that's fine, but the mere fact that there exists such a "perception" is a problem. I posit that it is not just one-off rude comments or snarky remarks that need addressing but a rather unfortunate large part of the SO ecosystem that needs attention.
I am just a lowly former active asker and (later) answerer of questions on SO. I am a cisgender white male and even I stopped participating in the SO community a number of years ago because I felt excluded. I can't imagine what it must be like to not possess the magic privilege triangle that I do and participate on SO without feeling disheartened by the toxicity that I feel has found a comfortable home on SO. 
I openly admit it is easy to sit on the sidelines and shout things like "The community is toxic! It is mean-spirited! It is elitist! It is discriminatory!" but if enough voices exclaim such things, or even (I think) if one voice whispers such things, then perhaps we ought to take a hard look at the community as a whole and see what we can change, then take whatever measures to enact said change. I am using "we" here and not "you" even though I haven't been active on SO for a number of years now, because I believe this duty falls on each of us as SO community members.
I owe a great deal to SO and the knowledge I gained here, and that's one of the main reasons I wanted to contribute back by answering any and all questions I could. I don't post this to simply finger-point or make dissenting remarks, but rather because I still, after all these years, care about SO and its mission as originally laid out all those years ago, and because I do believe SO still has a chance of becoming an inclusive, nice place to ask questions and contribute to a vast database of knowledge if we all pitch in. But only if we admit that perhaps these problems exist, and take measures to make things right, instead of saying things like "well it never happened to me" or "well the bar for nicety has been raised in society" as ways of making ourselves feel better.
I've seen in the past, and see currently even in the remarks on this question, people asking for "hard data" about the exclusionary, elitist, and generally condescending atmosphere that exists on SO. I think that's a valiant pursuit, but quantifying such things with numbers and statistics is insanely difficult and, I believe, misses the point. The mere fact that people are feeling this way and voicing the fact that they are feeling this way should be enough for all of us to realize things need to change.
I'm not even sure I believe the idea that "the bar for being nice" has been moved up over the years as has been suggested in this question's answers. Perhaps though there is some truth to that, and even if there is, what's wrong then with raising the "bar" for the SO community as a whole? Did it ever hurt anyone to take a few moments to re-format your comment or your answer to be a bit more empathetic and compassionate?
For example, put yourself in the shoes of a new SO member who wants to ask a question. Said member has a very good chance her question will get obliterated (read: closed/deleted/) by the community (often with remarks like: "Read about how to ask a question before posting" or "this question has been asked a thousand times already!" or worse) simply because she didn't read every page of SO's stringent guidelines for asking questions.
I understand the goals of such community guidelines and principles are to keep content quality as high as possible, but I firmly believe that compassion, empathy, and inclusiveness do not share mutually exclusive relationships with quality, as has also been suggested in this questions answers/comments. Quite the opposite, in fact. And, even if (gasp) quality were to sometimes take a smaller backseat to compassion and kindness, wouldn't we all benefit? At the end of the day, SO is a community of humans and not computers right? But I guess I come from a mindset that "content quality" (what does that really even mean?) would do well sometimes to take a huge backseat to making people feel welcome and included. That's the only "quality" that matters at the end of the day for me. 
My plea to the SO community at large is that we finally take a good hard look at ourselves in the mirror and admit there are things that need to change, and then make those changes.
Finally, in German it is sometimes said: Man kann nicht alle in eine Schublade stecken which roughly translates to: "One can't throw everyone in the same drawer." In other words, I don't want to make the claim that everyone on SO has made the community a toxic place, or that there aren't even people fighting actively in the trenches to help the community become a more inclusive place, I'm simply imploring all of us to realize that SO has a problem, and we all need to do our part to fix it. Jeff & Joel had a brilliant idea with StackOverflow, but they are not infallible, and neither is the community they started. Let's start to make things right.
Update: First, I am somewhat taken aback that the top-rated comment on this answer effectively seems to be saying (at least to me) that it's fine to be a jerk in the name of content quality. Really? Even if in the official SO guidelines to be nice? As the #1 source of QA developer information, is this the best we can do? Is this really how we all feel? Are we really happy with excluding people like this?
Secondly, I don't think we should be conflating the concepts of "being nice" or "being rude" with having compassion. Some of the comments on this answer mentioned that this "answer" is more of a statement of the problem than a solution. I admit that openly. Want concrete things we can do now? Let's rework the "Be Nice" page and get rid of the wishy washy "be nice" or "be rude" vocabulary and replace them with "compassion" and "empathy." Nice and rude are very subjective at the end of the day. One person's nice is another persons nasty. What isn't so subjective is having compassion and empathy, remembering that the person on the other end of the keyboard is a living breathing human being with feelings.
How about an update to moderator / user-mod guidelines as well? Add a suggestion that if you are getting upset about all the "bad questions" you are seeing than maybe it's time for you to step away from the keyboard yourself for a while. A community moderator, whether elected or user-mod, should never let their emotions affect their decisions or comments.
How about a blog post, or a serious of blog posts admitting that there IS indeed a less-than-ideal culture existent on SO and that we want to take, and are taking, measures to rectify it. 
How about the staff reaching out to the developer community at large, on channels other than SO, and asking for honest non-SO community feedback. Ask THEM why they feel excluded instead of speculating in the (sometimes) echo-chamber that is SO meta.
Jeff himself mentioned that if we want to become better programmers, we should take ownership and figure out how things might be our fault. I think this is great advice and applies to the SO community as well. Even if we at first think we are doing nothing wrong, how about we take a few steps back and evaluate how we might IN FACT be doing some things wrong?
Will we ever satisfy everyone? No. But that's not what I'm after / the intent of my post. But can we create a welcoming, inclusive, compassionate community? Yes. I really believe we can.
Those are just a few concrete suggestions/ideas I have that may slowly help change the culture and make SO a truly welcoming and inclusive place.

