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.
designed to solicit opinions or best-practices on a particular topic, with the goal of reaching community consensus.
You need help with the use of one or more of the site's features.
used for questions about whether something fits within the defined scope of this Stack Exchange site.
whenever you have any queries regarding the status of yours or any other users question or if you need any information/tips on how to frame a question
For questions concerning tags synonyms on both the main site and meta.
for discussion of single-word-request questions asked on the main site.