Even within a site's relatively focused range of topics (it's unlikely anybody on SO will think refers to the solar system's star), some tags are inherently ambiguous.

There are currently two unsatisfying options:

  1. Declare that the tag is only to be used for one of the possible meanings, write a tag wiki explaining it, and link from there to the newly created tags for the other meanings, and keep cleaning up the tag whenever someone ignores the tag wiki popup explaining the tag.
  2. Use alternative tags for all meanings (e.g. cd-command and compact-disk, instead of cd), and keep removing the undesired tag whenever it pops up again. And it will. The rep requirement is not deterring users from creating unnecessary or redundant tags.

Blacklisting tags is a complicated ritual occurring once in a blue moon, at most, and involves a dragon, a team member, and sacrifices to be burnt. It also makes those other, unambiguous tags not easier to discover, if it were applied to ambiguous tags. I don't consider this to be a viable option in this case.


Here's the proposed :

Just like a tag can be declared a synonym of another tag, basically changing all references to the synonym to references to that other, canonical tag, it should be possible to make it a disambiguation tag (or ambiguous tag) for multiple other tags. It's a logical progression from "You entered a term with the same meaning as this other term" to "You entered a term with the same meaning as one of these other terms, please choose the correct meaning".

Use of the tag should force the user to choose one of the alternatives presented:

Not all of these examples might be good (I'm not sure e.g. about the first two SO examples), but that's not really the point here anyway — they should just convey how this could be used.

Note how some of these tags would probably never be used if users had to type them, and yet everything shorter is ambiguous.

This could probably be mostly solved by extending the synonym/tag wiki excerpt dropdowns shown when a user enters the tags, proposing the alternatives for an ambiguous tag entered by the user (like a synonym suggestion, but with multiple options). If ignored, the user could still be shown an error message like with blacklisted tags, but by designing the selection dialog well, it should be possible to prevent that in most cases.

Mockup of error message when the user ignores unambiguous tag suggestions

Related topics

  • 5
    we need one for db as well
    – prusswan
    Commented Mar 10, 2012 at 15:13
  • 39
    I like it, but it is a bigish job. I predict that it will take 6--8 weeks. Commented Mar 10, 2012 at 16:50
  • 21
    Brilliant idea, solves the problems I've been trying to figure out a solution for for a long time, like the ambiguous (and therefore useless) [vb] tag. (Oh, hey, and you even knew that because you linked to my question. How about that!) Commented Mar 11, 2012 at 1:04
  • Why does this site even use tags? Why not just depend on full-text-search for search?
    – Rosinante
    Commented Mar 12, 2012 at 2:36
  • 4
    @Rosinante: You can follow tags. Searches are fuzzy logic, with 95% accuracy at best when everyone uses the right jargon in their questions. Tags, when properly applied (and high-rep users can enforce this when other people don't), can be 99%+ accurate and less chance of bleedover from a fuzzy match into a totally different subject area. Plus, with the tag system you can hint accurately (as this feature request proposes). Woe betide the SE dev who tries to implement Clippy.
    – user172164
    Commented Mar 12, 2012 at 4:00
  • 3
    Wikipedia has a similar feature when you search for a word with many referents such as, well, vb. Commented Mar 12, 2012 at 9:04
  • 1
    Kind of an aside, but maybe some implementation of the above feature request might allow for it: apparently there are also valid non-ambiguous tags that are confused for other tags. It might be nice if a warning can be shown for those too, but then still allowing one to choose the original tag.
    – Arjan
    Commented Mar 16, 2012 at 20:53
  • 1
    What happens to existing questions with ambiguous tags if this request gets implemented? That sounds like /hyperbole/ hours for Moderators.
    – Sam DeHaan
    Commented May 1, 2012 at 18:25
  • 1
    @SamDeHaan Good question. My suggestion: Let's just prevent new topics and edits from having (or keeping) these and let the community fix everything that's older (like blacklisted question title terms — the problem problem — AFAIK). Commented May 1, 2012 at 20:18
  • 3
    It would be great if someone from SE would weigh in on this, even with a "We're thinking about it". Ambiguous tagging and the cleanup necessary to deal with it does seem to be a constant problem.
    – razlebe
    Commented Jun 7, 2012 at 18:48
  • 5
    I ♥ this. And yeah, it would be really cool to get at least some acknowledgement from the team and a hint on how they feel about it
    – Pekka
    Commented Jun 12, 2012 at 20:50
  • 3
    I really like this idea. I just hope the color of the popup will be given a bit more thought ;)
    – PeeHaa
    Commented Jun 12, 2012 at 21:23
  • @PeeHaa I'm sure the developers are smart enough to use #fe7a15 for SO. The screenshot was created on SU, where this is the .supernovabg color... Commented Jun 14, 2012 at 17:59
  • 1
    “it's unlikely anybody on SO will think sun refers to the solar system's star”. Oh really? Mind you, the sun tag should probably go — SO questions are about solaris or sparc or sun-jvm or what have you, not about the former company. Commented Nov 7, 2013 at 17:51
  • So, will this ever be implemented?
    – vacip
    Commented May 22, 2016 at 22:40

5 Answers 5


My biggest issue with ambiguous tags is that writing tag wiki for these is a torture.

* For , am I supposed to write about Windows Media Audio format or about Java ME Wireless Messaging API?
  For , am I supposed to write about USB Communications Device Class or about Change Data Capture in SQL Server or about Connected Device Configuration in Java ME?

And even if I decide to cover all popular meanings in tag wiki, imagining how it would look like to reader makes me sick. Two, three, more totally different topics to cover at single page? give me a break!

As far as I can tell, proposed feature request helps to get rid of that headache which is why I am all for it.

  • 13
    The solution so far (at least on SU) is to make each of them stand for only one thing (determined from convention or meta discussions), and if you want to tag with the alternative meaning, you need to find another tag. You can imagine how well that works. Commented Mar 12, 2012 at 6:18
  • 3
    @DanielBeck yeah I can imagine. That's why I upvoted your feature request
    – gnat
    Commented Mar 12, 2012 at 6:30
  • This is old, but: How about a simple "This is a disambiguation tag for [x], [y], [z]"?
    – Jan Doggen
    Commented Sep 20, 2023 at 14:03

As far as I can see, tags on these sites need a tuneup, and I don't think that this proposal goes far enough.

Commonly, bad questions are accompanied by 'a tag sentence'. Low-rep users just start typing away in the tag field, and discover that the 1000 most commonly used words in English are all existing tags, possibly including 'a' and 'is' on a bad day. As far as techo-jargon goes, I think that the tag box might be turing equivalent, containing as it does essentially all of the keywords of all commonly used programming languages.

At this point in, at least, stackoverflow's maturity, I wonder if it would make more sense to require high-rep action to bring a new tag into existence. When someone with a middling amount of rep used a tag for the first time, it would not be available to anyone else until a high-rep user or mod explicitly endorsed it.

  • 3
    Note that new users cannot create really stupid tags. Tag creation on SO is a 1500 rep action, unfortunately an invisible one. The tag will simply exist if you enter it. And new users will happily select mac, os and x, instead of mac-os-x, that's true. Regarding keywords, that seems like a problem specific to SO and should be discussed separately. Commented Mar 12, 2012 at 6:20
  • 14
    This is something a simple decision for commas instead of spaces as tag separator could have prevented. Oh well. One battle at a time. Commented Mar 12, 2012 at 6:25
  • I believe on SO it's an entirely different issue. On SU, for example, reviewing the new tags created in the last 30 days is absolutely possible (we just need a few more 10k-users to do it).
    – slhck
    Commented Mar 12, 2012 at 11:06
  • 1
    Well, then we have some not-so-new users spinning straw into not-gold all the time.
    – Rosinante
    Commented Mar 12, 2012 at 16:27
  • 5
    Is it possible to make tag creation require the user to write at least a 20 character tag wiki, to prevent accidental or stupid tag creation? Commented Jun 12, 2012 at 18:44
  • 1
    @daniel commas also work as tag separators. Try it yourself... Commented Jun 12, 2012 at 20:06
  • 1
    I think that the tag box might be turing equivalent :D !! nice one
    – hek2mgl
    Commented Jan 28, 2014 at 21:50

As an active user of Microsoft Unity, I always try to protect the tag unity (which is firstly used for that product) from misusage.

Two key points that I think should be added to this proposal is,

Friend Tags for Each Tags For each tags, we should allow friend tags to be defined. For example,

  • unity should have inverse-of-control, dependency-injection, ioc, and so on.
  • ubuntu-unity should have ubuntu and so on.
  • unity3d should have 3d, game, and so on.

Automatic Suggestions As each questions can have 5 tags, we can tell from the other tags whether the usage of unity is correct or not.

For example, if a user uses ubuntu and unity, he/she must mean ubuntu-unity, and we should generate a warning.

If a user uses '3d' and 'unity', he/she must mean 'unity3d', and we should warn too.

Only when the ambuguous tag is the only tag used, we display all ambiguous options equally. This is more convenient, as users can easily learn which option is most likely the proper one to use.

  • 1
    I like the idea of a "friend" tag. But I'm afraid it will only help in those cases, where the OP even adds more than one tag! Commented May 27, 2013 at 11:14
  • 4
    Looks like an interesting optimization to the disambiguation process. This can probably be automated as well, as the system knows which tags are frequently used in combination, so no need to manually define those. Commented May 29, 2013 at 20:40

Re-edit: As was pointed out to me in the comments - There are some points that should be addressed about the proposal.

Possible Solution:

Require that Tags need to have a minimum 100 character description in their wiki to be used. All current tags that are considered ambiguous can have the Wiki entry replaced with 'ambiguous - use either A, or B'.

They cannot be applied to any posts until this happens, and an error that says soemthing like "users can't apply new tags without a description on the tag wiki. The tag 'stupid-tag' is new and/or has an insufficient length. Try using an existing tag instead, or writing a new description if you are sure this tag describes something different than those that already exist."

The creation of a Tag Wiki would be changed to be a 1500 reputation locked action. These locked tags could then not be applied to existing posts until a decision is made on how to make them non-ambiguous or they are left too short, so that they need to be abandoned.

People could, over time, make edits to these older, badly tagged posts to fix the tagging. Edits to old posts would not allow people to leave any newly non-acceptable tags on the posts.

  • 3
    That's an unnecessary bottleneck to cover an exceptional case.
    – Toomai
    Commented Jun 12, 2012 at 19:00
  • What will happen: Not yet existing tags for new topics just don't get created by the original question authors, since it's too big of an effort. Increased question maintenance by reviewers and editors. Users will create unused tags to "prepare" for questions, but tag auto-deletion (for cleanup) is applied to zero question tags. Since this approach will make 0 question tags a required part of the system, the tag cleanup will have to be redesigned. Negative impact and side effects are just too severe to make this approach useful. Commented Jun 12, 2012 at 19:26
  • Daniel - Good call, and you may be 100% correct. I was unaware of the auto cleanup issue. (Pleading ignorance isn't really an excuse.) How often does the auto cleanup run? Could it have a very minor modification and just exclude any tags created in the last 5 minutes? Commented Jun 12, 2012 at 19:33
  • Toomai - The exceptional case should be the creation of a new tag. I would expect that for almost all situations, there should already be a tag, since tags should be reused frequently. If no tag exists, it means that the specific subject is completely novel to the site. (Unlikely, since we aggregate knowledge in topics that relate to the site.) Commented Jun 12, 2012 at 19:36
  • 8
    this is actually a great idea -- it adds exactly the right kind of friction to new tag creation, namely "if you really really want this new tag, you gotta know what it is and explain it to everyone else a little first. Commented Jun 12, 2012 at 20:07
  • @JeffAtwood - it may be a good idea, but implementing it is much heavier than I had expected. I wanted the frictional cost to increase for users, which was the idea, but the implementation sounds like it would be way too heavy. Commented Jun 12, 2012 at 20:12
  • Jeff - Also, it's cool to interact with you - I'm a big fan of yours. Commented Jun 12, 2012 at 20:14
  • 1
    The real issue with this solution: You're basically suggesting "unsatisfying option 1" from the question, with enforced tag wikis that can (and will) be ignored. As I wrote in the original question, users don't care what the tag wiki (excerpt) says -- they'll happily select the mac tag for software issues. Commented Jun 14, 2012 at 17:27
  • I understand that it could occur that way, but it makes more sense to me to remove mac, replace it with machintosh, and then make the mac tag a short explanation: This is ambiguous. See [Link] about why not to use it. Commented Jun 14, 2012 at 19:43
  • This makes mac a meta tag. I don't know whether ambiguous tag woulld solve the mac problem, and that's not the point. It was just an example that users ignore tag wiki excerpts when selecting tags, making your answer ineffective. Commented Jun 15, 2012 at 4:08
  • Making it into a short explanation would, under the proposal, nuke the tag. That could be called a meta tag, but I would prefer calling it a deletion, with a note. I could be done more universally, to remove tags that are ambiguous, and while the meta-tag rule is a good one, this proposal would serve to modify it slightly to allow a category of meta- but effectively deleted tags. Commented Jun 15, 2012 at 11:26
  • 1
    It looks to me that you are suggesting a similar solution to my feature request, but achieve the desired effect through a hack (short explanations are used for undesired tags), and not through properly implementing the specific solution to the problem you want to solve, e.g. by automatically showing the desired tags as autocompletions (like with today's synonyms). What is the advantage of your proposal, other than the obvious (requiring tag wikis)? It will require just as much development, and will not be as clear, requiring users to learn the "short description" hack. Commented Jun 15, 2012 at 16:04
  • 1
    While I applaud the effort of getting more and better tag wikis, the method to require tag descriptions for tag creation/use will be a significant obstacle to tag creation, with severe side effects, such as a) no new tags will be created anymore, even if they are useful (possibly good on SO but painful elsewhere) b) repetitive, useless tag wikis that just so manage to get past the character count requirement. Comments already have minimal length requirements which is often achieved through random useless padding. I prefer no tag wiki to useless tag wiki -- the former is easier to identify. Commented Jun 15, 2012 at 16:06
  • @DanielBeck That is fair. The idea was that it would be much easier to implement. If this is untrue, it may not be helpful. The problem of gaming tag lengths isn't something that occurred to me, but is a fair one. The issue that SO has different challenges than other SE sites is also not something I had thought through fully. On the other hand, adding friction would slow useless tag creation, and might cause people to consider what they are doing a bit more. Commented Jun 15, 2012 at 16:13

Another solution might be to make it better known, or have a gui front end such that you can easily do a multiple tag query. For instance, the "table" tag is overloaded. If you just click on the button for "table", you will end up with posts that deal with different subjects, notably sql database tables and html tables. But if you go to the box at the top right and type

[table] [sql]

then you get a list of questions dealing almost exclusively with database tables.

Alternatively, if you type

[html] [table]

you will get a list of questions almost entirely related to html tables.

With multi-tag queries the problem of overloading goes mostly away so it should be promoted somehow.

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