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.
For questions about the sites chat rooms - https://chat.stackexchange.com/?tab=site&host=interpersonal.stackexchange.com
Requests for tags to be changed or edited, typically by a Moderator.
For questions about the Winter Bash (or holiday hats) to celebrate the end of the year.
About questions that may be refined to a certain region, or how regional questions should be dealt with.