Traditionally, CAPTCHAs and reCAPTCHAs are used to identify humans. The technique is largely used in preventing computer scripts from flooding or entering applications meant for users. For example on CrazyEngineers we used reCAPTCHA for registration form to prevent computer scripts from creating fake accounts and then spamming on the forums. However according to latest news reCAPTCHA have been broken as well. That calls for newer techniques to be developed to distinguish between humans and computer programs. Facebook has taken a social approach to verifying humans. They'll present a list of your facebook friends and give you options of names. If you choose the correct name, you'll be allowed to pass through. What new ideas do you have for human verification on the Internet?