In the early days of digital culture, Jaron Lanier helped craft a vision for the internet as public commons where humanity could share its knowledge -- but even then, this vision was haunted by the dark side of how it could turn out: with personal devices that control our lives, monitor our data and feed us stimuli. (Sound familiar?) In this visionary talk, Lanier reflects on a "globally tragic, astoundingly ridiculous mistake" companies like Google and Facebook made at the foundation of digital culture -- and how we can undo it. "We cannot have a society in which, if two people wish to communicate, the only way that can happen is if it's financed by a third person who wishes to manipulate them," he says.