He is one of the people that created a program that stopped multiple spam accounts on yahoo and other famous web sites.
Remember you have to type those silly words that you can't even read before you register or leave a comment on a web site or blog?
Well, now he has a new project he is putting all the books ever written by mankind on the Internet but he has problem.
A computer cannot decipher ancient words written by man.
So, next time you see Recaptcha try to solve it for Luis.
Those are real copy of ancient words found in books all over the world.
You just have to type the exact words and the computer will register those words.