Ogilvy has signed a deal Eyetools to test email campaigns by looking at what people looks or ignores. Ok, I'll say it better: using a camera embedded in the monitor, OgilvyOne will follow eyes movement patterns of people reading commercial email. The idea is to investigate what recipients actually read and what they ignore.
It's called eye-tracking and it's usually a practice used in psychology and medical research. Since advertising people are going crazy to get people attention, Ogilvy's study perfectly makes sense.