One of their projects is the attempt to digitize the contents of every book ever written, and making that information searchable in their famous search engine.
One of the remarkable (and under publicized) tools for searching the already massive database of text from books is called the Ngram Viewer. It is quite simple. You enter search terms separated by commas and the Viewer searches books back into the mists of history. You are presented with a graph showing how often each term appeared, giving you a visual representation of just how pervasive a concept has been, over time, in the public consciousness.
I have included several examples. You can play with the Ngram Viewer at: http://ngrams.googlelabs.com/