Usage guidelines
Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to prevent abuse by commercial parties, including placing technical restrictions on automated querying.

We also ask that you:
+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for personal, non-commercial purposes.
+ Refrain from automated querying Do not send automated queries of any sort to Google’s system: If you are conducting research on machine translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the use of public domain materials for these purposes and may be able to help.
+ Maintain attribution The Google “watermark” you see on each file is essential for informing people about this project and helping them find additional materials through Google Book Search. Please do not remove it.
+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other countries. Whether a book is still in copyright varies from country to country, and we can’t offer guidance on whether any specific use of any specific book is allowed. Please do not assume that a book’s appearance in Google Book Search means it can be used in any manner anywhere in the world. Copyright infringement liability can be quite severe.

These are all “suggestions” as near as I can tell. As with the Chicken Coupon fiasco of a few days ago, the implied threat that comes along with this item puts a bit of a damper on the joy that is the public domain. Bleh. We’ve seen other big corporations and libraries doing this as well.

However, this post is mostly to say “Yay” about Cornell’s decision to remove all restrictions on the use of its public domain reproductions. Here’s their press release about it and here is the web page with the new policy. What’s their reasoning? Well among other thigns it’s hard to support a misson of open access and at the same time go out of your way to make materials more difficult to get ahold of and interact with. You can see some of Cornell’s 70,000 public domain items at the Internet Archive.