Thanks very much for reading my paper and for writing such a thoughtful response!
Thanks also for the clarification on the LCSH aggregation. For the purposes of this (exploratory) research, I was attempting to limit the comparison to just the headings assigned within the LC catalog, but if/when I delve deeper, I'll be sure to take this into account.
SIG/CR provided a great opportunity to engage in conversation about folksonomies and controlled vocabularies: interested parties may want to visit the conference paper archive at DLIST to read more.