Abstract
Folksonomies have emerged as a means to create order in a rapidly expanding information environment whose existing means to organize content have been strained. This paper examines folksonomies from an evolutionary perspective, viewing the changing conditions of the information environment as having given rise to organization adaptations in order to ensure information "survival" - remaining findable. This essay traces historical information organization mechanisms, the conditions that gave rise to folksonomies, and the scholarly response, review, and recommendations for the future of folksonomies.

From catalogablog: 

Smith, Tiffany (2007) Cataloging and You: Measuring the Efficacy of a Folksonomy for Subject Analysis. In Lussky, Joan, Eds. Proceedings 18th Workshop of the American Society for Information Science and Technology Special Interest Group in Classification Research, Milwaukee, Wisconsin.

A Columbia Librarian posted a long article about tagging systems and their use in libraries. Interesting reading.