The inspiration for this question comes from the boost libraries where boost itself has a tag, and, almost, every library within boost has a tag. So, when I'm (re)tagging a question that involves one of these dependent tags, do I also add the parent tag in addition to the dependent specific tag? With only 5 tags allowed, adding the parent tag restricts the ability to classify these questions, and yet without it, the question can't be found by simply selecting the parent tag. Also, if it is recommended to include the parent tag, how deep do you go? For instance, boost.spirit has two subgroup tags itself: qi and karma.
I'm looking for guidance on what is the "proper" thing to do here, to add the parent tag or not? Although, it does suggest that we may want a tag hierarchy so that tagging with a dependent tag automatically implies the parent(s). But, that may be more work than it is worth.