Just as the automobile radically changed people's lives at the beginning of the 20th century, so too has the revolution in online services (including blogging, podcasting, videogaming, shopping, and social networking) and cell-phone use changed our lives at the turn of the 21st century. In addition, many other services, activities, and devices--including the Palm Pilot, the BlackBerry, the iPod, digital cameras, and cell cameras--have been made...