The increased demand for measuring campaign results and new technologies that create more natural test settings have prompted some ad agencies to again take a gander at a research discipline that's been around a while: eye-tracking. AdAge writes that WPP Group's OgilvyOne recently struck a deal with eye-tracking firm Eyetools to test email marketing for clients such as IBM, American Express and Cisco.

Preliminary results have held some "surprises": the word "free" is often skipped, and the majority of readers see less than half of the email copy.

A camera in the frame of computer monitors tracks what portions of emails test subjects are paying attention to and what they're ignoring - without having to wear headgear or goggles, or being strapped into an electric-chair-like contraption. The results are depicted in a heat map or diagram that shows the pattern of eye movements across the email.