A free tutorial website, Duolingo, aims to translate the entire web with the help of people starting to learn a new language. It's a project born out of guilt from the man behind one of the most annoying features of web surfing - those online security checks involving random words.
Duolingo hopes to convince millions of people to work for free and thus translate all web content in a matter of years.
It may sound like an ambitious plan but it's not the first time founder Luis von Ahn and his colleagues at Carnegie Mellon University have enlisted a global workforce to work for nothing.
As a 22-year-old graduate student in 2000, von Ahn invented the Captcha - those distorted images of words and numbers used to sign in to ticketing and social media websites, among others, which users have to decipher to prove they are human.
