See the full essay for some additional details about fine print in Google's plan
From the user's perspective, the possibility of using the Internet to access a book, particularly a hard-to-find book, from one of the large libraries of the world is obviously wonderful. However, it is important to clarify what Google is offering: it is not a digital text that the library will be able to share unconditionally with others. In its contracts with the nineteen libraries now in its consortium, Google has stipulated that the "Universal Digital Copy" of digitized books it provides must be protected from non-Google Web software; and that the number of downloads from texts digitized by Google will be limited. Only Google can aggregate collections of different libraries in order to create the larger digital database that is the most valuable part of the consortium project.