I would say absolutely, because on Google Books you can do a full search. Even if you have a very specific search term and the book only displays 20%, you can still access 20% of the exact term that you want. Especially for small publishers, academic publishers, and publishers who publish in something specific, it really does drive a lot of traffic, at least to the website and at least to the publisher. I do see it as a tool to market to not only readers in North America, but all over the world. We have web traffic from Google Books from all over the world.
On November 4th, 2010. See this statement in context.