The first thirty years of the twentieth century demonstrated that attention could be harvested on a mass scale and converted into unprecedented levels of commerce and military might. It is therefore remarkable that this effort—which seemed at the time so pervasive, to the point of inflaming critics and whole movements—was, in retrospect, so circumscribed in time and place. To see where and when attention was being harvested, one had only to see where advertising (or propaganda, its noncommercial twin) was to be found. For however inescapable and multifarious it may have seemed at the time, advertising before 1930 was confined to the oldest of media, those from the nineteenth century or earlier—newspapers, magazines, billboards—and the oldest of the major communication networks, the mail system. It had as yet no purchase on the new media of the twentieth century, which were only beginning to transform the lives of those who heard and watched them—the movies, radio, and soon, television. Furthermore, there remained a divide between the highly commercialized public sphere and the traditional private one. A newspaper or leaflet might be brought inside, but otherwise the family home was shielded from the commercial bombardment to which one was subjected in public.

Tim Wu, The Attention Merchants, loc. 285