In cooperation with the Library of Congress Flickr started a project called "The Commons" where users can tag 1500 pictures of the collection of the Library of Congress.
C. Hänger, and C. Krätzsch. Wissenschaftskommunikation der Zukunft 4. Konferenz der Zentralbibliothek, volume 18 of Schriften des Forschungszentrums Jülich, Reihe Bibliothek / Library, (2007)