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.
The question you're asking is designed to solicit opinions or best-practices on a particular topic, with the goal of reaching community consensus.
For questions asking for help with the use of one or more of the site's features.
For questions about tags: proposals to create, synonymise, merge, or remove tags, questions about usage guidance for particular tags, etc.
when examining what is on-topic or off-topic, and why.
For use when inquiring about a particular question e.g. inquiring about a specific question's suitability for this site.
for new functionality you want, which cannot be achieved by current tools or moderation efforts.
For questions about the closing of questions: whether, when, why, and how questions should be closed.
For questions regarding the design elements of the main and meta sites e.g. CSS issues
For questions about closing questions, or about a specific closed question.
referring to the process of identifying and closing questions that are duplicates of another question.
For questions relating specifically to posts with the [story-identification] tag on the main site.
should be used on posts relating to figures that are important to the Science Fiction and Fantasy:SE community who've recently passed away.
For questions about the Science Fiction & Fantasy community blog.
For questions about the real time, stateful web chat.
For questions relating to spoilers, content about a work (movie or book) that some users may not know yet,
For questions about tag synonyms: either existing synonyms or proposals to create new synonyms.
For use when discussing the appropriateness and use of comments
For questions about the Meta site, scifi.meta.stackexchange.com itself.
Elections are held to choose moderators for non-Beta Stack Exchange sites.
For questions related to upvoting or downvoting posts, or the workings of the voting mechanisms themselves.
For questions about the moderation policies of the site and actions taken by moderators.
For questions about the review queues: the section of the site where users with sufficient reputation can review others' posts, e.g. for possible closure or deletion, and suggested edits.