So what
is the significance of tagging for the librarian?
For the more radical thinkers in the tagging space, folksonomies represent a revolution in the knowledge classification - as emergent, evolutionary ontology rather than the authority based systems we have had in the past. To these writers, Clay Shirky chief among them, tagging rings the death knell for the traditional systems of library classification, replaced by a fluid system of self-created categories that evolve with use.
The question is essentially one of centralization. What works better - a swarm of "virtual catalogers" all tagging away towards some rough consensus, or a centralized authoritarian body classifying to a strict schema, a "priesthood" of information? Does the system evolve from the top-down, or bottom-up?
For many in the library world, this is understandably their worst nightmare. Librarians are not to be faulted for feeling as though the hard-won lessons of the profession are in danger of being swept away on yet another rising tide of revolutionary rhetoric. The organization of knowledge is the very fundament of the library profession. If librarians are nothing else, they have been the keepers of the Great Outline of human knowledge.
So is the profession doomed? My guess is that, as with so many other areas condemned to death by the technological pundits, we will eventually see a middle ground. While we can't expect to see people start tagging their posts with Dewey numbers, we can perhaps hope to see some agreement and refinement of the universe of tags. Such a step would perhaps limit the bottom-up, emergent nature of folksonomy. In the long run it could provide a rudimentary authority, increasing its utility and efficiency as an information resource.