I posted this because a number of friends and clients were asking me about WEB2.0 buzz words they are hearing.
Wikipedia defines a Folksonomy as "A folksonomy is an Internet-based information retrieval methodology consisting of collaboratively generated, open-ended labels that categorize content such as Web pages, online photographs, and Web links. A folksonomy is most notably contrasted from a taxonomy in that the authors of the labeling system are often the main users (and sometimes originators) of the content to which the labels are applied. The labels are commonly known as tags and the labeling process is called tagging."
Folksonomies can work well for a number of sites requiring information classification, particularly where popular categories are required. We have all seen the populous defining appropriate categories in sites such as Flickr and del.icio.us / http://del.icio.us/help/tags.
The idea of socially constructed classification schemes, ie without the benefit of an information architect could be frought with problems. Something I haven't come across but would love to see is the integration of a social thesaurus.