AdAge wrote about Ogilvy optimizing emails with heatmaps and eyetracking.

This is an Eyetools 'heatmap' of the hottest spots of attention on one email. Click to see larger eyetracking image.

Ogilvy's director of email campaigns, Jeanniey Mullen sees strategic benefit in adding objective feedback/testing into their design process -- they want to always improve the quality delivered to their end-clients.

Ogilvy picked Eyetools as their email testing supplier because of our speed and experience in the space. We're proud of this!