I find it difficult to understand why we expend so much effort and discussion on tags.
I’ve browsed around other SE sites, and I can see that tags serve a useful, perhaps even essential, purpose in filtering questions related to a specific language or application. But I don’t see a similar purpose served by the tags we employ.
Of the top ten tags at this writing, only one (pronunciation) seems to me useful in trying to discover prior questions relevant to a specific problem; the rest are too general and vague to have any value. None really provides the sort of information found in a good index to a book: some (verb, grammar) provide the equivalent of chapter titles, but most (word-usage, difference, meaning, phrase-usage, proper-word, word-choice,word-request) speak to nothing more substantive than the motive for the question or the form of answer required.
On the one hand, all of our questions are about meaning and grammar and usage, at least in the senses people use those tags. On the other hand, looking for previous proper-word or word-choice or word-request questions seems unlikely to yield me anything relevant to my question nearly as fast as just Searching on my key terms.
I have an awful feeling that tagging on this site is just categorizing for the sake of categorizing; but I’d like to be persuaded otherwise.
So: What purpose are tags supposed to serve, and do the tags we’re using actually serve that purpose?