Yes, you probably should be tagging your curriculum. There are many reasons cited in this article from TeachThought, but in addition to these, remember that open resources such as the Learning Registry, Online Communities of Practices/Connected Educators use metadata that can use these tags for discovery and knowledge building on a much larger scale.
“You probably should be tagging your curriculum.
It’s 2014. It’s time.
Tagging is is the labeling of content based on any chosen criteria.”
New Images of Education 