“Harvard’s library is making public the information on more than 12 million books, videos, audio recordings, images, manuscripts, maps, and more things inside Harvard’s 73 libraries.
“Harvard can’t put the actual content of much of this material online, owing to intellectual property laws, but this so-called metadata of things like titles, publication or recording dates, book sizes, or descriptions of what is in the video is also considered highly valuable material. Frequently descriptors of things like audio recordings are more valuable for search engines than the material itself. Search engines frequently rely on metadata over content, particularly when it can’t easily be scanned and understood.
[…]
“The release follows Harvard’s decision, via its Office of Scholarly Communications to release for free much of the published research from its faculty. The metadata will be available for bulk download both from Harvard and from the Digital Public Library of America, which is an effort to create a national public library online.”
From Quentin Hardy’s post on the New York Times‘ Bits blog, Harvard Releases Big Data for Books