What would you do if someone asked you to help transcribe an old book onto a website? Chances are, you'd say no on the basis that you have other things to do, or simply that it just doesn't sound very interesting. And yet, millions of people every day are helping with precisely this task, and most are completely unaware that they're helping out.
It's all thanks to a computer program developing by Luis von Ahn and colleagues at Carnegie Mellon University. Their goal was to slightly alter a simple task that all web users encounter and convert it from wasted time into something productive. That task - and you will all have done this before - is to look at an image of a distorted word and type what it is in a box. It often turns up when you're trying to post on a blog or sign up for ...
