@M.A.R.ಠ_ಠ I certainly don't know how to use tags effectively. Seems to me like a bit of a round-peg-square-hole problem. Tags were designed for SO, and we're reusing the SO software, so all the other sites have them too and they work the same way everywhere. That doesn't mean they're equally useful for all topics, though.

For natural language sites, I think a more hierarchical tag system might be better.

That is, something closer to categories than tags.

We're stuck with what we've got, though, and at this point it'd be pretty hard to change the massive library of existing questions, so even if we had a choice, I'm not sure if it would be feasible to switch to another system.

Sometimes you can't tag a question accurately unless you know the answer. If a question is about something, but the OP has no idea what that something is, not knowing that can be 90% of the problem.

Also, there's a huge mismatch between the various modern analyses of English and the analyses of centuries past much of the ELL user base clings to, and with that mismatch comes a huge terminological problem.

Even modern linguists often use different terms to describe the same things. Lump in various outdated analyses, and we've got a smorgasbord of terminology to choose from.

Worse, we often describe entirely different things with the same terms.

It's all a mess, but a mess is all you'll get in a crowdsourced Q&A environment.

I believe in ELL, but we pretty much have to live with the mess.

It's okay, because we can help people anyway.

It's not ideal, but it's okay.

If you want something that's comprehensive and self-consistent, you pretty much have to go out and write a book.

@ColleenV When we were all trying to retag grammar, I found there were questions where it was really difficult to pick something more specific.

Also, when the obvious tag is a technical term most people don't know, like "quasi-serial verb constructions" or the like, I've gotten a bit of resistance in the past.

@ColleenV Yeah, our goal is to help people. It's okay that we're a bit all over the place.

In the past, sometimes I'd add them and people would get annoyed and think, "What is this? Can't we just use plain English?" and then they'd remove them from all the questions.

I haven't added many technical terms as tags to the site lately.

Sometimes if I don't have much time, I think, "If I add a tag with this specific term, it'll let people know what the question is about, and then they can search for articles on that topic and find the answer".

It might not be the primary purpose of tagging, but I think it ends up helping sometimes with XY problems.

I don't have a problem with single-use tags, as long as I can imagine questions coming up in the future which will use that tag as well.

Some of the more esoteric topics might only have one or two questions at first.

They can still be useful for grouping in the long term.

I’m not a huge fan of those tags, but I’m not really against them, either. I think several were made simply to get hats, though, and not for any really constructive purpose.

The one thing that’s nice about those tags is that they make up for a flaw in the site search. It’s hard to search for questions that mention a function word rather than questions that use a function word, and if it’s stopworded you can’t search for either!

“Can I ask one more question?”

They can do that if they like.