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 issues related to comments that should have been answers.
A bounty is a way to get additional attention for a question by offering some of your own reputation for great answers.
for general questions about questions that have been closed because they are off-topic or otherwise do not meet the criteria defined in the FAQ.
for instructions and guidance on closing or migrating questions, and the reasons for those closures.
Community Wiki is a feature that can be applied to answers which lowers the barrier for editing and prevents any rep gain/loss from voting. With the introduction of suggested edits, Community Wiki is …
for questions specific to downvotes, the community's way of telling peers that their content can be improved. Downvotes on the Meta site have different meanings to on the main site.
For questions about the process of editing, how edits work, and other general inquiries about the edit system.
Elections are held to choose moderators for all graduated sites and some beta sites.
about ethical implications of operations research; examples may concern data privacy, scientific integrity, etc.
For questions about events organized OR.SE or other Stack Exchange communities.