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 concerning using images in questions, image hosting etc.
answered by the same user.
Users without full edit privileges can suggest edits to posts and tag wikis
Per-site lists of tags that cannot be created.
Questions about diamond (♦) moderators, their powers, and actions they have taken.
For questions about the real time web chat that accompanies Sports Stack Exchange.