Is it appropriate to modify the tags of a question to better reflect the issues that appear important with respect to answers?

If the answer is yes, how far can it go?

For example, an answer might show that the question is just a special case of something more general that could call for somewhat less specific tags.

My concern is that tags are supposed to help find the information, not just the question.

Another possibility would be to allow some extra tags on the questions ... but that is proably a significant implementation change.

  • 1
    $\begingroup$ Do you have specific examples in mind? This is a bit difficult to discuss in the abstract. $\endgroup$ May 9, 2015 at 22:04
  • $\begingroup$ Is there a limit on the number of tags? Or more to the point, is there a restrictive limit to the number of tags? $\endgroup$ May 19, 2015 at 8:36
  • $\begingroup$ @LukeMathieson A question cannot have more than 5 tags (from experience: I did not read it anywhere, but the sytem does not seem to like more). $\endgroup$
    – babou
    May 19, 2015 at 9:57
  • $\begingroup$ @Gilles I had this question in mind for some time. The one case that prompted the question was this question. I thought it might be appropriate to add the tag closure-properties, but it also felt like I was advertising my own answer rather than the question. As it turned out, the tag was added by Hendrik Jan (after you asked for an example), which is a contribution to answering this question. $\endgroup$
    – babou
    May 19, 2015 at 10:06

1 Answer 1


It can be appropriate to retag a question to use tags that the asker wouldn't have thought of before reading the answers. If the asker's problem is a well-known one and the solution intrinsically calls for concepts that the asker didn't know about, then adding tags corresponding to these concepts is warranted.

Fictional example: someone asks whether it's possible to generalize regular languages and finite automata to parse nested parentheses, with the tags . Answers will naturally mention context-free languages and pushdown automata. Adding the tags and would be reasonable, because the question is also useful for people who do know what PDAs are but not their applicability to parsing parentheses.

Strictly speaking, tags should not be driven by answers. For example, tagging a question about a concept that an answer describes in detail, but that other good answers to the question might not mention at all, wouldn't be appropriate. But the choice of tags can be driven by more knowledge about the question than what the asker has. Tags are for everybody who might be looking for the question.


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