What does Duolingo do with the translated documents?
That's a good question that I don't know the answer to (but I am also curious about that).
My impression is that right now they don't do anything with them at all. I think the site is still working to get the kinks out and the "final" translations are generally still to poor to release. But, my understanding of things from watching Luis' TED talk, is that eventually people and companies will contract with Duolingo for translation services, and once documents have been translated, they'll presumably be returned to those entities to use as they see fit.
I understand that they may sell documents translated from English but not vice-versa. I wonder does anyone in Duolingo look at finished articles, or do they simply disappear. I am thinking of long articles where someone has translated most of the article but no one else has read it?