In Silicon Valley, the cradle of digital technology located south of San Francisco, an army of bright young engineers holds so much data about our lives that it has become all-powerful. Led by the four giants of the Internet, known by the acronym Gafa (Google, Apple, Facebook and Amazon), to which we can add Microsoft, this "empire of the future" rebats the world maps by interfering, including via smartphones, in all human interactions. Zuckerberg versus Trump