OCLC Research has released Social Metadata for Libraries, Archives, and Museums, Part 1: Site Reviews.
Here's an excerpt from the press release:
Traditionally, staff at libraries, archives, and museums (LAMs) create metadata for the content they manage. However, social metadata—content contributed by users—is evolving as a way to both augment and recontextualize the content and metadata created by LAMs. Many cultural heritage institutions are interested in gaining a better understanding of social metadata and also learning how to best utilize their users' expertise to enrich their descriptive metadata and improve their users' experiences.
In order to facilitate this, a 21-member RLG Partners Social Metadata Working Group reviewed 76 sites relevant to libraries, archives, and museums that supported such social media features as tagging, comments, reviews, images, videos, ratings, recommendations, lists, links to related articles, etc. In addition, working group members surveyed site managers, analyzed the survey results and discussed the factors that contribute to successful—and not so successful—use of social metadata. They also considered issues related to assessment, content, policies, technology, and vocabularies.
This report includes an environmental scan of 76 social metadata sites and a detailed review of 24 representative sites.