The following is an edited section from http://en.wikipedia.org/wiki/Google_books, accessed July 8, 2011:
12 million books: Google (July 2010).
2.8 million books: Internet Archive is a non-profit which digitizes over 1000 books a day, as well as mirror bookss books from Google Books and other sources. As of May 2011, it hosted over 2.8 million public domain books, greater than the approximate 1 million public domain books at Google Books.
6 million digital objects: HathiTrust maintains HathiTrust Digital Library since 13 October 2008, which preserves and provides access to material scanned by Google, some of the Internet Archive books, and some scanned locally by partner institutions. As of May 2010, it includes about 6 million volumes, over 1 million of which are public domain.
10 million digital objects: Europeana links to roughly 10 million digital objects as of 2010, including video, photos, paintings, audio, maps, manuscripts, printed books, and newspapers from the past 2,000 years of European history from over 1,000 archives in the European Union.
800,000 digital objects: Gallica from the French National Library links to about 800,000 digitized books, newspapers, manuscripts, maps and drawings, etc. Created in 1997, the digital library continues to expand at a rate of about 5000 new documents per month. Since the end of 2008, most of the new scanned documents are available in image and text formats. Most of these documents are written in French.
1+ million art images: Artstor: "is a non-profit organization that builds and distributes the Digital Library, an online resource of more than one million images in the arts, architecture, humanities, and sciences. The ARTstor Digital Library also includes a set of software tools to view, present, and manage images for research and teaching purposes. There are currently more than 1,300 ARTstor institutional subscribers in over 42 countries" (http://en.wikipedia.org/wiki/ARTstor).