This is big news -- though still only part of Harvard's full collection of records.
Following the British Library's release of 3M bib records under CC0 18 months ago: http://isites.harvard.edu/icb/icb.do?keyword=k77982&pageid=icb.page49837...
David Weinberger writes:
This is the largest contribution of full bib records we know of.
Stuart Shieber [of the Berkman Center] (and of the Office of Scholarly Communication) was the driving force behind this.
Woohoo!
David W.