Compound Tagging - Next Big Thing

Does this mean that 'tags' can now to be used for more objective sorting of data, such as a multi-dimensional Dewey Decimal System? If so, I hope these tags are appropriately applied to each work- I would hate to miss out on content simply because it was tagged haphazardly.

I imagined tags to be useful for classifying content in a subjective manner. Tags are to content as blogs are to events.