What are they?
Tags are a helpful tool for marking an Ad, Ad Set or Campaign to make reporting and discovery faster and easier inside AdRules. There can be one or many Tags attached to a creative element. Tags reside in AdRules and are not sent into Facebook. For example, tagging Ad Sets allows you to efficiently revisit ads based on specific tests you are running: date, gender, sku, etc.
You can hide/display your tags by going to the tag dropdown button.
Ad Set & Media tags can be their own column on Advanced Reporting. To add Ad Set, or Media tags as a column, go to Settings under the Data dropdown and make the selection.