In "Google Book Search Settlement: Foster Competition, Escrow the Scans," Peter Eckersley proposes that digitized books involved in the Google Book Search Settlement Agreement be put in escrow for some period, then made freely available.
Here's an excerpt:
One good compromise might be to require that anyone who takes a blanket license (whether under the Google Book Search settlement, or under any legislation that might expand the settlement to others) must deposit a copy of the raw scans that they create with the Library of Congress or with the entity that administers the blanket license (e.g., the Books Rights Registry). After a period of years, let's say 14, the term of the Founder's Copyright, those scans should be made available at no cost to any others who take the relevant copyright licenses.
This would not only encourage market entry and competition in the online digital books arena, but would also foster innovation in the field. There's nothing that encourages digital innovation quite like access to an enormous dataset. After all, before Larry Page and Sergey Brin founded Google, they were graduate students at Stanford. They were able to build a new search engine by downloading their own copy of the web, messing around with it, and figuring our a better algorithm for querying it. New start-ups working with digital books should have the same kind of opportunity.