I watched a cool and short video about n-grams created from 5 million books by using Google’s computational power.
Here is a little background info about N-gram: http://en.wikipedia.org/wiki/N-gram
N-grams are used in natural language processing (NLP) a lot. We can basically say that they are mostly used to guess the next word according to the previous word sequence.
Google’s N-gram viewer: https://books.google.com/ngrams/