Seems like pretty much every question is a usage question, so keeping around a "usage" tag seems about as pointless as having a "programming" tag at Stack Overflow would be.
Does anyone object to my re-tagging questions to not have the pointless tag "usage"?
I personally hope there will be quite a few questions not related to usage, but rather underlying structure and modelling that, phonetic properties, etc. I can imagine quite a few questions that aren't usage questions, and am finding it hard to see why the extra tag hurts in general when removing it would certainly hurt other questions like these.
Of course, this has a lot to do with whether or not this Q&A site is for primarily for usage questions, or about the nature of English, and why it is the way it is.
I could see value in usage if it were used for questions of when is it appropriate/usual to use a word (or tense, or whatever). There might be a better tag to get across the idea - e.g. connotation or dialect - but the person asking the question may not know which of those applies, at least until the question is answered, which puts the questioner in a lovely chicken-and-egg situation. Unfortunately, I don't think this is how usage has been used on the site - too often, it's a meaningless catch-all "I have to add a tag" tag.
I thought at one point that usage would cover a distinct subset of topics found on "English & Usage" but now I am not so sure. Having a usage tag that takes its name from the site name itself would seem to imply an English tag. But now that Jeff has burninated the English tag, it just seems a little redundant. At some point it's all usage ... even pronunciation. You can't interact with a language at all without, I don't know, using it ... right?
When I see a question tagged with usage, I understand that the OP is more interested in which cases the word/phrase is used, or in which contexts should be used. For example, if I ask about the usage of the word earthlink, I am more interested in which cases I should use the word, rather than to its meaning; if somebody replies saying what the word means, s/he is not giving the answer I am expecting.
I think that usage, meaning, and etymology are three different aspects of a phrase, even if they are connected.
It's not at all clear what "usage" means, even if you go and look at the questions which are tagged with this tag. I think most people are adding it to the questions just out of laziness. If someone thinks this tag is useful, what should be added to the tag wiki? I have no idea.