When you fill out a CAPTCHA on a or TicketMaster

When you fill out a CAPTCHA on a social network Facebook, Twitter or TicketMaster you’re actually helping to decode scanned words from books that computers have trouble deciphering

Collaboration between humans and big computers to solve global problems is the topic of my pick for TED Talk of the week. The talk is called “Massive-scale online collaboration” by Luis von Ahn, a Carnegie Mellon computer science professor, entrepreneur, and pioneer in human computation.Luis helped create the CAPTCHA — those squiggly letters you have to type into web forms to prove that you’re really human — and later, CAPTCHA. As he explains in this video, once CAPTCHA went worldwide he realized that he helped waste a lot of people’s time everyday by having to enter this info (even if it was for a good cause — security) so he wondered if there was a way to make this time more useful.The result was CAPTCHA, which combines with the Project Gutenberg and Google Books to use reCAPTCHA to help decipher words that computers can’t understand when scanning books into digital format. That’s why reCAPTCHA has two words for you to enter. One of them is authenticating your human-ness and the other is translating a word that computers couldn’t read when scanning a book. The process is remarkably accurate.There are now 350,000 sites using reCAPTCHA, which results in people helping translate 100 million words a day, or 2.5 million books a year.  The magic happens “one word at a time from people typing CAPTCHAs on the Interent,” said von Ahn. To date, 750 million people (or 10% of world’s population) have participated in reCAPTCHA and helped translate at least one word from a digitized book. That’s the big “Ah ha!” for Luis and it’s what he has chosen to focus his research on, as he explains on his Carnegie Mellon bio: