From the Goddard Space Flight Center , CC Attribution 2.0 Generic
As you may have seen in our recent Sneak Peek post, we’ve been working on new ways to allow you to browse subject headings in Open Library. Edward’s just built a new subject search index too, so you’ll be able to do a keyword search for any/all subject headings that mention that word.
Testing things and looking around, I wondered about comparison between two different systems of classification: Library of Congress Subject Headings (or Authorities) and Flickr tags.