Luis von Ahn is an ambitious guy. He’s best known for putting a twist on CAPTCHAs – the squiggly fragments of text that websites deploy to beat spammers’ automated software – that he called reCAPTCHA. Von Ahn realised that when we solve a CAPTCHA we could be helping to decipher text that book-digitisation software has tried and failed to transcribe. Google liked the idea so much that it bought reCAPTCHA in 2009, and now uses the technique to help power its book-scanning project.
Von Ahn‘s current project may be his most ambitious yet. Duolingo is a website where people can learn a language for free and help to translate web content at the same time. Not everyone thinks it will work, but von Ahn now has evidence that one part of the challenge – the learning bit – is performing as hoped.