Here is a great application of social tagging for a museum collection at the Philadelphia Museum of Art. Users can add their own tags to the online collection. Each item has a base record of necessary information like the title, artist, date, collection, etc. However, by allowing users to add tags, the museum can find out how people really search for these items, encourage interaction with the collection, and make the whole experience a little social. The museum also has a nice FB page. Rocky Balboa would be proud.