Taxonomies vs. Folksonomies

Bloug: Folksonomies? How about Metadata Ecologies?: Jan 06, 2005: Folksonomies? How about Metadata Ecologies?

"Lately, you can't surf information architecture blogs for five minutes without stumbling on a discussion of folksonomies (there; it happened again!). As sites like Flickr and del.icio.us successfully utilize informal tags developed by communities of users, it's easy to say that the social networkers have figured out what the librarians haven't: a way to make metadata work in widely distributed and heretofore disconnected content collections."

This is a good starting point for finding reasoned discussion by knowledgeable people on the pros and cons of taxonomies vs. folksonomies (AKA "mob indexing")