I recently saw an untagged tag, supposedly created by Community
One of our helpful users has proposed the following as tag wiki excerpt:
This is a special tag that is designed to be used only by the system for questions that have had all of their other tags removed. Do not add this tag to existing questions, it is reserved for use by the system to identify posts with no valid tags.
I had a look at the tag and 8 questions, even one highly upvoted one, seem to be tagged with untagged, which is strange as I remember this particular question certainly had a relevant tag in the beginning (I can't remember what exactly the tag was though, sorry).
What is untagged, and what can we do about questions that have become untagged?