If you've ever had to type in a bunch of funny looking letters and/or numbers when registering for a site or making a purchase online, then you've experienced CAPTCHA. Google has now acquired reCAPTCHA, a provider of the secure measure.
What sets reCAPTCHA apart from other providers is that it uses scanned archives to provide the funny looking text. reCAPTCHA then uses Optical Character Recognition (OCR) to convert the scan to text.
Google plans to harness the technology for its Google Books and Google News Archive Search.