Some questions tend to get asked in thousands and thousands of permutations.

One such type of question is questions on Apache's mod_rewrite. This list of questions tagged .htaccess catches most (not all) of them. There are three "please write my rewrite rule for me" type questions today alone. My feeling is that one such question ("I want this and that kind of URL to be redirected to this and that file") comes up every day at least once.

Other examples are:

  • "Headers already sent" (PHP)

  • How do I let a container wrap around floated child elements? (HTML)

  • I get garbled special characters on my web page (HTML / (my)SQL / Unicode)

  • And hundreds, if not thousands more.

They are always very, very specific, so they can't really be closed as duplicates of anything else. Still, essentially, one quick run-down with a few examples would do for many of these. Instead, they usually get answered after some time. Because of their specificity, and their vast numbers, it is my opinion that many of these questions have little value for future generations.

What do you think?

Is this being perceived as a problem?

Does this warrant a whole new kind of close reason with a link to a FAQ page or reference question or something? That's what floats in my mind as the right solution.

Do we need a master question for these to close the other questions as a duplicate of?


starting a bounty to incite some more discussion.

  • 6
    Kind of like: stackoverflow.com/questions/tagged/regex
    – random
    Commented Aug 25, 2010 at 15:31
  • 1
    Oh come on, why don't you mention the almost perpetual flood of Cross Domain .load() or how to create layout with X fixed and Y fluid columns, or float and vertical-align and centering a div questions, etc etc...
    – Yi Jiang
    Commented Aug 25, 2010 at 15:40
  • 1
    @Yi Jiang they follow the same pattern. I picked mod_rewrite as an example, those kinds of questions probably can be found in every tag.
    – Pekka
    Commented Aug 25, 2010 at 16:02
  • @Yi Jiang by the way, feel free to edit those questions in if you want. But, seeing as it's been viewed 42 times, and upvoted once, it doesn't seem to provoke much reaction in the community, so maybe it's not worth the effort.
    – Pekka
    Commented Aug 25, 2010 at 18:20
  • 1
    Three hours and you're already calling time of death? Very Kevorkian.
    – random
    Commented Aug 25, 2010 at 18:22
  • @random ahahaha! Well, true. You never know.
    – Pekka
    Commented Aug 25, 2010 at 18:23
  • 7
    Like "Vote to close as No More Fish"?
    – random
    Commented Aug 25, 2010 at 18:29
  • 1
    @Pekka, meta.stackexchange.com/questions/61960/…
    – Pops
    Commented Aug 25, 2010 at 18:39
  • @Pekka, yes, simply omit the space and the notification should fire.
    – Pops
    Commented Aug 25, 2010 at 18:54
  • @Popular ah, good to know! Cheers. @YiJiang there are comment replies for you.
    – Pekka
    Commented Aug 25, 2010 at 18:58
  • 1
    Try again. Only the first name gets pinged about @comment addressing.
    – random
    Commented Aug 25, 2010 at 19:03
  • @YiJiang, there are replies for you. @random damn, this system is so complicated. Thanks
    – Pekka
    Commented Aug 25, 2010 at 19:07
  • possible duplicate of Are Duplicates creating broken windows? Commented Aug 25, 2010 at 20:32
  • 1
    Convenience link to this question's sister question Do "reference questions" make sense?
    – Pops
    Commented Nov 22, 2010 at 16:18
  • 1

8 Answers 8

  1. Make one generic question on the topic.
  2. Answer with a concise, clear and awesome guide, with headers, examples and anything.
  3. Accept the bestest answer
  4. Put a link to it into the relevant tag wikis, for what is worth.
  5. Turn it community wiki and bless it with a red "featured" tag. (← mod assistance reqd.)

Now answer the other questions by pointing to the relevant bit of that one "wiki."

Why bother?

If people come up with a question all the time, it means there's no one authoritative, clear enough source of information on the topic.

Just make one.

  • @radp I feel the same way, but I did just that a while back, and had it closed: stackoverflow.com/questions/3650125/…
    – Pekka
    Commented Nov 22, 2010 at 15:19
  • 1
    I'm pretty sure the [featured] tag only has meaning on meta.
    – Aarobot
    Commented Nov 22, 2010 at 15:41
  • 9
    I also must violently disagree with your second section. Repetition does not mean that there's no authoritative source; it just means that people are too lazy to look it up. How many times do you see users who clearly haven't even read the first paragraph of the official FAQ? Or ask questions that are answered very prominently in the FAQ?
    – Aarobot
    Commented Nov 22, 2010 at 15:44
  • 6
    > If people come up with a question all the time, it means there's no one authoritative, clear enough source of information on the topic. ~ Or it could mean they're all lazy ...
    – jcolebrand
    Commented Nov 22, 2010 at 15:57
  • That's fine as long as (a) nobody gets reputation for posting a FAQ link, and (b) nobody else answers the question directly. Neither of those are assured with your solution. And as Pekka has suggested, the community seems to have a problem with canonical questions, even when they've basically been pre-approved.
    – Aarobot
    Commented Nov 22, 2010 at 15:59
  • @Aarobot, if a FAQ links gave you no rep, why would one post it in the first place, given that people swarm these questions mainly for the rep (imho)?
    – badp
    Commented Nov 22, 2010 at 16:02
  • 3
    @radp: That's exactly my point. This problem shouldn't be solved by answering questions, it should be solved by moderation - closing as a duplicate of the FAQ. And people who answer need to have any rep gain canceled. But even with that, the OP is still getting what he wants by being lazy, because other lazy people will still swarm the question without checking for dupes. That's why I think mario has a good point - their answers should actually be made invisible to the OP so that he doesn't get what he wants until he learns to read the damn FAQ.
    – Aarobot
    Commented Nov 22, 2010 at 16:02
  • @Aarobot If you think moderation can do so on a timely manner, then great! Since however answers cannot be moderated by non-diamond-mods I'm afraid this really can't work.
    – badp
    Commented Nov 22, 2010 at 17:19
  • @radp: I never said moderation should apply to the answers. Moderation should be done on questions, same as before. The answers should just be de-repped and probably hidden from the OP. It's not like this hasn't been discussed a thousand times already, it just isn't getting implemented because of the fifth column who love the easy rep they get from dupes.
    – Aarobot
    Commented Nov 22, 2010 at 17:49
  • 3
    I also believe this is a good idea in itself. Artificial questions that strive for high quality and designed answers can raise the overall site usefulness. They would be particularily useful to closevote duplicates. However, the community sometimes rejects synthetic questions and answers (even if community wiki). It's worth to keep trying it, but the influence on newbiews shouldn't be overestimated.
    – mario
    Commented Nov 22, 2010 at 19:00

I'd like to exemplify with:
PHP Warning Cannot modify header information

The meta topic here would be that it's caused by language misdesign, but anyway it's a real issue. The web and most bulletin boards are polluted with question like this, and despite better base design even Stackoverflow is affected. Two solutions:

Systemic Prohibition

Let's be honest. The influx of these questions is caused by laziness. Posting a new question on Stackoverflow always brings up matching duplicates for "Warning Cannot modify header information". Some askers just refuse to use that feature and the search function. Or expect other people to debug for them, explain basic language features or want prosaic recitations of the manual.

Anyway, filtering might help here. A simple regex check on question and question title should suffice to detect the majority of these excessive duplicates. (We'll have to make a list though.) And if the new question form detects it, it should just bring up an extra confirmation box:

The system detected that your question is most likely a duplicate. If you have used the search function before and checked out some of the suggested links, then check this box [x]. Otherwise please do so now. Your question would likely be closed without answers if it's a repetitive duplicate.

Well, it works for spammers. And I assume it's at least likely to reduce the amount of annoying duplicates. So, let's not postpone the list making.

   "/Warning:?\sCannot\smodify\sheader\sinformation/": "https://stackoverflow.com/search?q=%5Bphp%5D+Warning%3A+Cannot+modify+header+information",


Evil Plan B

This is not an proposal, nor an announcement, but it's not a fun answer either.

Be realistic. Excessive duplicate questions are actively encouraged by the SO commmunity. Whenever one of those boring, stupid or annoying duplicate questions is posted, 10 people jump immediately to the rescue and answer it. (While the more interesting questions seemingly go ignored on weeks.)
But that's only natural. Gaining reputation is fun, and that's why people flock to simple (and sometimes dull) questions.

However this very human behaviour draws boring askers to Stackoverflow. If you reward them, they will come. And closevoting questions is no serious discouragement. Likewise are admonishing comments no functional repellent. Therefore I charily suggest "censoring" the overhelpful answers on useless duplicates. If a duplicate is closevoted quickly enough it's redundant. But if someone answers it, it's imperative to kill off those answers on the spot. I'd use something along a standard replacement template like:

Search for [php] Warning Cannot modify header information
The question is a duplicate and has been asked too many times before. +1 for effort on this answer, but links should be sufficient here.

Needs rewording. It partially punishes the answerer, but should make it clear that the purpose is censoring the stupid question. And one needs to take care not to wipe the sporadic extraordinarily good answers, and whatnot. If the answerer is appalled by this method, a discussion may ensue, or he can just revert it back if it seems unjust.

Yet, I think this is the only realistic deterrant against <PROBLEM OF THE WEEK>. A real stop to answering stupid duplicates will send a clear message. A blood font might also help.

  • 1
    I don't think regular expressions are going to work here, but plan B has a point. One deterrent to answer dupes that has been discussed is not to give reputation for them - there are some questions, like the one you mention, that I would like to see that for.
    – Pekka
    Commented Nov 22, 2010 at 10:07
  • -1 for suggesting we should be dicks to askers.
    – badp
    Commented Nov 22, 2010 at 15:09
  • 3
    @radp: We shouldn't be dicks to anybody, but neither should we reward help vampires - and unfortunately, the latter is exactly what both the system and community actively and consistently do.
    – Aarobot
    Commented Nov 22, 2010 at 15:41
  • 2
    @Aarobot The problem, as this answer puts it, is that easier questions generally bring you more (or far more) reputation than others, because they get far more traffic and far more people vote on the topic. The solution, then, is reducing the rep involved.
    – badp
    Commented Nov 22, 2010 at 15:49
  • @radp: Yes, eliminating dupe rep is an important part of the solution. However, as long as the questions get answered at all, it encourages the vamps.
    – Aarobot
    Commented Nov 22, 2010 at 15:56
  • 2015: We do have lots of great reference questions meanwhile. And while it hasn't completely solved the repetition patterns, they're now easier to deal with. New users are way better served with concise summaries and even cross-referenced answer links. Both the new search function and duplicate auto suggestion did help. Yet newcomers still stumble over heaps of not-so-stellar "try this / try that" answers when researching topics. (I generally think it more believable now when questions start with "Searched this for hours, but couldn't find a suitable answer).
    – mario
    Commented Aug 22, 2015 at 20:38

I'm going to take a pessimistic view on this topic, seeing as how it has been covered many times in one form or another and never truly resolved...

Q: What can be done about repetitive questions?

A: Absolutely nothing.

I think there are too many "human factors" involved for this to be dealt with effectively. Here are some:

  • Users that are lazy: Even if you made the most comprehensive FAQ to deal with an oft-duplicated question or set of questions, the user still has to find and read it! This requires them to search first (good luck with that) and even if they did that they would find a mammoth FAQ, and they would probably look at it and say "Geez, TL;DR. I'm just going to ask my question." What's worse, if there are already a slew of duplicate questions present, and a user does a search and gets a huge list of them, then that list could also probably elicit a "Geez, TL;DR." since they might find it easier to ask a question than read through a whole bunch for their answer.

  • Users that think they (and their problems) are unique: When a user asks a duplicate question, you can often see the comments devolve into hair-splitting discussions like "I used the word "thinga" and the other question used the word "dongdong", so my question is different." Even if the core problem (and it's solution) are the same, they still take offense to the idea of their question being closed. Even if the answers they've received thus far are just rehashes of the answers to the other question, they still think their question is unique and deserves to stay open.

  • Lower-Rep users (Rep < 3000) that don't help: Obviously, if a user doesn't have the ability to close yet, they are limited in their ability to deal with duplicates. They could post links to duplicates in comments or upvote comments listing duplicates, but they're new enough to SO that they probably aren't very familiar with what the most pervasive duplicate questions are anyway. They may eagerly answer thinking that it's (somehow) the first time that an easy question like that was ever asked. Oh how wrong they are.

  • Mid-range users (3000 < Rep < 10000) that don't help: They have the ability to close duplicates now, but why waste time on this when they can easily gain Rep by answering the question, bringing them that much closer to partial mod privileges and nerd fame? They've probably had enough experience on SO to know what the oft-duplicated questions are, and they probably know how to find them easily. But hell, they could just copy from answers on the duplicates. Easy Rep is easy!

  • High-Rep (Rep > 10000) users that don't help: You've got a lot of experience on the site. You know what the common duplicates are, and you can find them, but you answer anyway. Sometimes you even answer the duplicate by brazenly posting a link to your own previous answer on the older question! And you don't vote to close duplicates much either. How is this helping the site? As a high-Rep user, you are more visible than others. New users will often pay more attention to your behaviors and accept them as the norm (e.g. "If high-Rep user X can ask a question like Y, why was mine closed?"). If you answer duplicates, not only are you setting a bad example to the greater community, but you're reinforcing the idea in the head of the question asker that it doesn't matter if they search first or not, they'll still get an answer from someone. Then again, maybe you just don't care about this or think it's a big deal. And that's your prerogative, but I don't personally find it all that helpful.

So, there are a lot of things that may lead users to disregard duplicates. Laziness, pride, ignorance, greed, apathy... this is why questions will keep getting duplicated with minor variations time and again.


Honestly, I don't think there's much more we can do about it, since we're kinda fighting against human nature here. Just keep trying to close them when you find them (and when you still have votes left), ask the mods for merges, and if you want to get into a fight with those who think that every duplicate is special, you can try to thin the herd of duplicates by voting to delete some.

...and yes, I see the irony in answering a question that is itself quite repetitive. ;)

  • 4
    +1 for a blatantly realistic assessment! In my opinion, there is one thing that could be improved easily by changing the system slightly: Making it easier to close questions as dupes, by having easily findable (and well-upvoted) reference questions to common problems - be they artificially created, or "real" questions. Everything else I do agree with: Much of what's happening is human nature
    – Pekka
    Commented Nov 22, 2010 at 21:19
  • @Rejoice: You have a point that having one canonical "reference" question could make it easier for closers to choose a link to use when closing as a duplicate, instead of having to choose from amongst a sea of questions with minor variations. I usually just go with the oldest one myself. Commented Nov 22, 2010 at 21:27
  • yeah. I tend to go for the highest-voted one - while that is not the perfectly right metric, it's the only one visible in the list (apart from views). I sometimes think one should be able to see the questions with the highest-voted answer(s) when choosing, to provide the asker with the best possible original
    – Pekka
    Commented Nov 22, 2010 at 21:32

They are always very, very specific

So close them as "too localized".

  • 2
    you are probably right, but this isn't happening. I have not seen any of them being closed as too localized, and a few lone riders starting to do so is probably not going to help.
    – Pekka
    Commented Aug 25, 2010 at 20:32
  • We've also had people whine about questions being closed as Too Localized and claim that it goes against the mission of the site. Then again, some people will whine about virtually any closing...
    – Aarobot
    Commented Aug 25, 2010 at 21:01
  • 1
    This is perfectly correct but it doesn't help much because (1) it may lead to hurt feelings and (2) the kind of people who write these questions are likely to be non-searchers, so most of them will just go right ahead and then they'll be annoyed and not helped out which leads back to (1) again. ::sigh:: Commented Nov 22, 2010 at 7:59
  • We should encourage specific questions, then people will come to get them answered, sucking more people into SO addiction. Commented Nov 22, 2010 at 19:37

The suggestion I have (well wish) is being able to close a question with "too many similar permutations, figure it yourself". As I feel providing answers fo these type of questions (and a signficant amount of questions on SO) are rewarding bad behaviour, how are people meant to learn to problem solve if they keep being provided with the answer.


How about allow users (with appropriate rep level) to flag as similar (instead of dupe) and post a link to 'propose' as the original question asked that it is a dupe of. Then if approved by say 3 users (again of appropriate rep level) and/or a moderator, the question gets closed as a duplicate and a link to the question that it is a dupe of.

Important to note would be comments and answers that were posted to the dupe question should be listed under the question that is the approved original with a link to the dupe question. That way when users view the original question they can see all answers there including the ones from the dupe but can still look at the duplicate answers in context by going to the dupe question.

Of course still allow votes to restore the dupe question back to non-dupe if the appropriate number of votes by appropriate rep level users and approval accordingly. However, I think the questions should remain linked since they are obviously similar.

I think it is important to preserve the original context of the dupe especially for restoral purposes. Furthermore, this process would allow linking of questions as similar, but not exact dupes (unless they get approved as dupes).


If a question is closed as a duplicate, given no reputation bonus, or a reduced reputation bonus, to those who answered the question and got their answer up-voted or accepted.

This will reduce the perverse incentive of the current system, which rewards people who fire off a quick answer to the all-too-familiar question, rather than put in the greater effort to find the question it is a duplicate of and to vote to close.


Honestly, I don't see a problem with duplicate questions. Seriously.

Every question is likely to have slightly different context, and that context can help people that other similar questions might not. In addition to that, SO is about helping people get their questions answered, not simply building a wiki-like knowledge base of only one answer to any given kind of question.

Finally, there may be a good answer that comes out of a later duplicate question that is better than all the previous ones.

  • your last point is important. there are always better ways of doing things. Commented Nov 22, 2010 at 6:34
  • 2
    As for your last point, this is why we need a way to merge answers when questions are closed as duplicate. Too often, what happens instead is that the question closed as duplicate (which has new and better answers than the earlier version) is actually deleted, along with those answers. Commented Nov 22, 2010 at 9:03

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