untagged does not mean anything. Any question should at least belong to one tag, so this is useless. It should be burninated.
Note: I had retagged the questions that had untagged to their corresponding tags.
You misunderstand the purpose of untagged.
It is a system tag that is used for questions that only have one tag, so that when that tag is destroyed they aren't "broken". We can't do anything about it without breaking the system.