Jonathan at the AGNSW pointed me towards this rather excellent piece on folksonomies which really resonates with our own experiences with our collection database.
What Vander Wal realized is that socially exposed tagging for personal use introduces another organizing agent that compensates for the ambiguity of its vocabulary with high-value serendipity: people. We are much better at picking up information and knowledge cues based on perceived similarities and differences compared to other people, than we are at picking up clues from a people-free environment. If people-free environments gives us weak serendipity, person-mediated serendipity is much richer.
People are a useful organizing agent because they are natural knowledge attractors and aggregators of meaning. People habitually collect and arrange for themselves what Vander Wal calls “personal infoclouds” and these arrangements reflect a meaningful perspective on knowledge (Vander Wal 2006).