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 Winter Bash (or holiday hats) to celebrate the end of the year.
Copyright - don't breach it
For questions pertaining to Workplace, a site about the workplace and other career-related topics, and how it relates to Programmers.
Questions about best practice questions at issue on the main site with people asking about them or why they don't work.