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" When a Web site requires you to retype a word as a security check, why is it so difficult to read? What security does this provide beyond flummoxing nearsighted hackers? Ah, the wondrous CAPTCHA, i.e., Completely Automated Public Turing test to tell Computers and Humans Apart. Luis von Ahn, a CAPTCHA pioneer and professor of computer science at Carnegie Mellon University, says that the goal is &amp;quot;making sure that whoever is entering the word is actually a human and not a computer program.  &amp;quot;You can use a computer program to vote ten million times in an online poll. Humans don&amp;#039;t have the patience to do something ten million times. CAPTCHA stops computer programs from doing the same thing over and over a gazillion times, like on Ticketmaster, with scalpers who would like to buy out an entire concert [by writing] a program that buys ten tickets at a time. With this security check, only humans can do it. If it was an image of clean text, optical character recognition would be able to do it. But since the characters are screwy, OCR can&amp;#039;t do it. The majority of the ones that are hard to read, it&amp;#039;s just because the CAPTCHA is badly programmed. It doesn&amp;#039;t have to be impossible to read. But if you try, you&amp;#039;re correct 97 percent of the time.&amp;quot; AF sincerely hopes that the remaining 3 percent are scalpers vulching tickets to Journey&amp;#039;s reunion tour. Got a question? Send it to answerfella@esquire.com.  "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.esquire.com/news-politics/news/a8146/captcha-alternatives-0910/>