As global advertising crashed in the 1930s, along with the rest of the economy, the industry was in existential crisis, and desperate to renew itself. With advertising's usefulness now in question, the old channels of attention could no longer generate enough revenue to keep the advertising business viable. So it began to search for others, and its search led it into what turned out to be human attention's mother lode. By means of new technologies, advertising and its master, commerce, would enter what had been for millennia our attention's main sanctuary—the home.

Tim Wu, The Attention Merchants, loc. 286