A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.
A tag for questions asking whether a specific question should be on-topic or off-topic. (I don't think we need a separate tag for on-topic and off-topic.)
Questions about the behaviour or usage of tags, which are keywords or labels that categorise and group your question with other, similar questions.
on-topic or off-topic for Korean Language SE, and why.
A tag for any question or suggestion related with Korean SE's Help Center pages and 2-minute Tour.
Questions about how to promote Korean Language SE, in order to attract more users.