By solving reCAPTCHA tests, millions of people unknowingly helped to digitise old books and newspapers.
Why it is true
Created in 2007 at Carnegie Mellon University, reCAPTCHA showed one known word and another that computers had failed to read on scanned pages. Human answers helped transcribe the New York Times archive and Google Books.
Source: Science (von Ahn et al., 2008)
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.
