Should tags be based on the answer(s)?

Question

Should good answers to a question influence which tags are appropriate for that question thread? In other words, are the tags dictated only by the content of the question, or by the content of the question plus the content of the good answer(s)?

Sometimes the poser of a question doesn't understand the various concepts involved (or chooses not to discuss his knowledge of it), so the question may directly relate to several concepts that are not mentioned. A good answer might clarify the question at hand and introduce a couple relevant concepts.

For example, a question may touch on the idea of a One Time Pad, and the OP will make no mention of it, but the accepted answer mentions and outlines the relevance of the OTP to the question. Or a question may ask about some general notion of the security of a block cipher and the best answer outlines how the semantic security definition addresses their question. If the original questions didn't mention or tag OTP and semantic security (respectively), should they?

I would think there is a general SE policy on this, but I didn't see anything. (And apologies if this is covered somewhere I should have been able to find it.)

Answer 1

Ultimately, tags are designed for two reasons:

• To help experts find questions in a topic area of their interest to answer.
• To help people seeking answers to the same question to find answers already provided.

Clearly, the OP not using the right tags doesn't help in the first case - because it takes an expert eye to understand what the question is really about.

However, it does help in the latter case. If you're looking for example for "AES Key Sizes", you could also search for [AES] Key Sizes which would search questions tagged aes, for "key sizes".

So, I'd say tags should cover the topic material covered in the question and anything that may be necessary to answer it, within the following constraints:

• Users, as you say, might not know which tags to use. We should be aware of this when re-tagging their question.
• They might actually not mean to invoke the topic we're thinking of adding as a tag at all. If in doubt, it might be worth seeking clarification.
• Any questions that need community consensus can be raised as questions here on meta, tagged specific-question taggingdiscussion. I'm imagining there won't be many that are that contentious, but the option is there and it is perfectly valid way to resolve a debate happening on a question.

So in short, I'd say yes, if the OP is amenable to the change. The more accurate the tagging, the better the search results are for us and so the more visitors and new users we get.