There is a place on the internet where almost two billion of us regularly go – many of us, every day. Facebook: the social network which Mark Zuckerberg started in his university dorm room and which has grown, in a little over a decade, into one of the most valuable companies in the world. But what does Facebook’s lines of computer code do with the data we give it – and what could it do in the future? Just how powerful is Facebook's algorithm? The answer will surprise you.

Produced by Estelle Doyle and Sarah Shebbeare This programme was first broadcast in April 2017.

(Facebook CEO Mark Zuckerberg delivers a keynote address during Facebook's F8 conference in San Francisco, California. Credit: Getty Images)