A “Captcha” program is one that captures human input before allowing new data to be posted to a blog, comment stream, etc. It displays some faint, fuzzy, or obscured text and asks the user to read and re-type it. Some folks have decided to put those keystrokes to good use. For their faint, fuzzy, or obscured text they are using scanned text from the digitizing of old books. The users thus become proof-readers for the digital library. Ingenious! Check out ReCAPTCHA and see if you can use it in your Web applications.
