The Ngram word search tool has been in use in Google Books since last year, but it was only today that Google ended the beta testing and added it officially.
Have you ever used the Ngram Viewer? It’s a clever little tool that allows you to search for a word in every eBook in Google Books. The Viewer then plots a graph that shows you how often the word appears based on when each eBook had originally been published.
If you like graphs then yes, it is as cool as it sounds. Unfortunately, it sometimes generates funky results. Take the above graph, for example. Most if not all of the mentions of the word eBook are due to errors in Google’s conversion process. Still, even with that flaw this is still a useful tool.