Karen Smith-Yoshimura for OCLC and her colleagues have recently published the third (and I think final) volume of what is now the definitive snapshot of the state of the art in the critically important area of social metadata for libraries, museums and archives. The three volumes, a newly available executive summary, and other ancillary material such as a recent webinar are all available at

Social Metadata for Libraries, Archives, and Museums

This is a wonderful resource, and I'm grateful to OCLC for developing it and making it broadly available.

Clifford Lynch Director, CNI