Both!

Jan 06, 2005: Folksonomies? How about Metadata Ecologies? "Neither works especially well on its own: controlled vocabularies often miss out on input from content authors and become rigid, stale, and distant from the vernacular of users; folksonomies will begin to break down...Treating them as major parts of a single metadata ecology might expose a useful symbiosis: encourage authors and users to generate folksonomies, and use those terms as candidates for inclusion in richer, more current controlled vocabularies that can evolve to best support findability."