Amazon xray feature
The new X-ray feature takes things a step further. Clicking on it will bring up a list of proper names, including characters, historical figures and places. It brings up a timeline illustration letting you know how often the name appears in the book viewable by page, chapter and the full text. Clicking on a character name will offer up a biography. Clicking on, say, the name of a historical figure, however, will pull up its Wikipedia entry. The entries, interestingly, aren't accessible over wireless, but are instead located in a side file that's downloads when you buy the book. It's a pretty neat little feature and one that may convince a smattering of pirating users to get their books through more legitimate means (i.e. the Kindle Store).