It seems to me that most of the questions about the one topic will also be related to the other. So why not have a single overarching tag like count-noncount or countability, and make countable-nouns and uncountable-nouns synonyms of this?
Since I'm talking about this, I'll also mention that the tag count seems of questionable usefulness to me; one of the questions tagged with it is about the countable-uncountable distinction, while others seem to be either about grammatical number or counting.
Anyway, do you agree with me? If so, what do you think is the best name for a tag about countable and uncountable uses of nouns? I'm leaning towards count-noncount, which you can find a lot of Google hits for, with countable-nouns, uncountable-nouns and their synonyms being made synonyms of this single tag.