Jamie Bartlett traces the story of how and why social media companies have become the new information gatekeepers, and what the decisions they make mean for all of us. It's 20 years since Facebook launched and the social media we know today - but it all started with a crazy idea to realise a hippie dream of building a "global consciousness". The plan was to build a connected world, where everyone could access everyone and everything all the time; to overthrow the old gatekeepers and set information free.

But social media didn't turn out that way. Instead of setting information free - a new digital elite conquered the world and turned themselves into the most powerful people on the planet. Now, they get to decide what billions of us see every day. They can amplify you. They can delete you. Their platforms can be used to coordinate social movements and insurrections. A content moderator thousands of miles away can change your life. What does this mean for democracy - and our shared reality? It starts in the summer of love, with a home-made book that taught the counter-culture how to build a new civilisation - and accidentally led to the creation of the first social media platform. But a momentous decision in the mid-2000s would turn social media into giant advertising companies - with dramatic ramifications for everyone. To understand how we arrived here, Jamie tracks down the author of a 1996 law which laid the groundwork for web 2.0; interviews the Twitter employees responsible for banning Donald Trump who explain the reality of 'content moderation'; and speaks to Facebook's most infamous whistle-blower in a dusty room in Oxford. He goes in search of people whose lives have been transformed by the decisions taken by these new gatekeepers: a father whose daughter's death was caused by social media, a Nobel prize winning journalist from the Philippines who decided to stand up to a dictator and the son of an Ethiopian professor determined to avenge his father's murder. Far from being over, Jamie discovers that the battle over who controls the world's information has only just begun.