Google has acquired reCAPTCHA and plans to use the system for digitizing books. Wait… what? CAPTCHA is the method of requiring a user to type in a visually obscured word to prove they are human. How can this digitize books? The answer is a bit obscure and takes some time to discover, but you’ll have fun along the way.

The Google blog links to a Google TechTalk video on Human Computation as an example of how they plan to use their new acquisition. It’s embedded below but at 51…