At the end of July, the AMC show Mad Men returns to television for its fourth season. The world of media and marketing has changed since the early 1960s advertising heyday. Aside from the obvious cultural changes (drinking, smoking and sexually harassing women in the office were completely acceptable, along with being racist, homophobic and anti-Semitic), the biggest difference is the introduction of an essential measurement that clients now expect their agencies to show: the marketing return on investment.
The Mad Men days were....