You cannot assume that simply because an ad is rendered in a browser that it has done its job.

Poynter's recently released Eyetrack III study hammered in that point. As Steve Outing says, "Ten seconds for an animated website ad to play out? Any advertiser who takes that creative approach is living a fantasy."

As we observed in Eyetrack when we looked at website banner advertising, the typical amount of time that people spend looking at an ad is usually less than a second -- when it's viewed at all. It varies based on ad content, size, and placement, but even the biggest ads only got a second and a half of viewing time in our study.

And here's another Eyetrack observation that speaks to Hespos' point: We noticed that animated ads sometimes did a better job of initially drawing the eye, but that static banner ads performed as well or better in terms of length of eye viewing and number of eye fixations (very brief pauses of the eye to take in information). The point: People didn't pause their eyes long enough to see the full ad animations.