Some tags are about topics that are blatantly not on-topic here. Let me quote the FAQ (I realize this is not the be-all and end-all, but it's better than nothing):
Mathematics Stack Exchange is for people studying mathematics at any level and professionals in related fields. We welcome questions about:
- Understanding mathematical concepts and theorems
- Hints on mathematical problems (but please read our FAQ about homework questions)
- History and development of mathematics
- Solving mathematical puzzles
- Software that mathematicians use (except Mathematica, which has its own Stack Exchange site)
Examples of such tags include career-development or publishing. Many of these tags are used on questions that would be better on other, newer SE sites such as academia.SE or workplace.SE, for example.
- What to do with questions using these tags? I think it's fair to say that a large percentage of them could be closed as off-topic, but that seems a bit drastic... I also understand that it's possible to make big migrations of questions happen for newer SE sites -- academia.SE and workplace.SE are already well-established, would that still be an option?
- What to do with the tags themselves? On the one hand they help identify problematic questions, and it's possible (though unlikely) that a question using these tags could be on-topic here (but such a question would certainly have other tags). On the other hand they deal with off-topic subjects, and their existence could be seen as a sign by question askers that their questions are, in fact, on-topic here.
- Another option: give a warning when such a tag is used. It's less drastic than outright banning them / migrating all the questions, but it would probably have a greater effect than a tag excerpt that people don't read. For example math-history could point out the new HSM.SE, physics could point out physics.SE, career-development could point out academia.SE and workplace.SE... I think I've already seen these warnings come in orange, if some feel the red color is too aggressive.