I used to say: if I didn't have Twitter I wouldn't have friends at school, in the early days, when everyone told me it was really Facebook that was cool. It's where I would go to say what I needed to say, but I thought nobody wanted to hear. Mostly Apple Keynote commentary, honestly.
In London, there is one CCTV camera for every fourteen people. But there are at least eight million residents with smartphones. When police brutality escalates in Hong Kong, and the murder of a black man is filmed by passers by in the US, they look like our greatest defence.