writes "In the cozy confines of personal life, we rarely used the power of numbers. The imposition on oneself of a regime of objective record keeping seemed ridiculous. And until a few years ago, it would have been pointless to seek self-knowledge through numbers. But now, writes Gary Wolf, technology can analyze every quotidian thing that happened to you today. 'Four things changed,' explains Wolf. 'First, electronic sensors got smaller and better. Second, people started carrying powerful computing devices, typically disguised as mobile phones. Third, social media made it seem normal to share everything. And fourth, we began to get an inkling of the rise of a global superintelligence known as the cloud.' And the next thing you know, exercise, sex, food, mood, location, alertness, productivity, even spiritual well-being are being tracked and measured, shared and displayed. Welcome to the data-driven life!"