We're at the beginning of an artificial intelligence revolution that promises to change everything. Already, virtual assistants like Siri and Alexa have become a part of our daily life. But in order to run their applications, digital giants like Amazon, Google and Facebook, employ an army of invisible labour. These are disposable workers, paid as little as 10 cents an hour to feed information into computer systems. They receive neither benefits nor contract and normal labor law doesn't apply to them. Whilst millions of men and women are training artificial intelligence for next to nothing, others are being hired and hide out of sight to clean up social networks. We went undercover as one of these web cleaners, working as a content moderator for Facebook. To meet the workers hiding behind your screen, we're taking you to the factory of the future, one of the digital economy's best kept secrets.