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 discussion about the explicitly commercial advertising that appears on this site (if any), as well as the Community Promotion Ads which are voted on by users of each site.
Requests to have a tag "burninated" (or deleted) from the system. Use in case of uncertainty when requesting discussion, or when the popularity of the tag makes manual retagging followed by automatic …