One of the great things about working at Google is the interesting kinds of data we have available, and the sheer quantity of it. It enables a lot of cutting-edge experiments, especially when you take the cross product of different areas of expertise. For example, Google has developed a lot of good technology for recognizing mentions of place names in text, as you might expect would be necessary for Local Search. Additionally, we've scanned and OCR'd a lot of books, as you might expect would be necessary for Book Search.
Today, a few friends of mine launched an exciting new feature of Book Search that exposes the result of applying our location-identification technology to the corpus of books. For a lot of books, the "about this book" page now includes a Google Map annotated with places mentioned in the book, where each annotation actually gives you the snippet of text that mentions that place. I've had a lot of fun exploring the results on some of my favorite books.
This is one of those interesting software products you really can only build at few companies, and I'm proud that Google is one of them.