Amazon's Improbable Phrases

How did I miss this? Amazon is analyzing the text of books to find Statistically Improbable Phrases (SIPs) contained within. This is a funny, interesting way to get a glimpse inside the book before you buy. For example, here are the SIPs for Gladwell's Blink: rapid cognition, intuitive repulsion, sip test, adaptive unconscious. (Overheard on #ETech.) I hope someone builds this for weblogs.