Marketers have used impressions and viewability as a proxy for engagement, but the real question remains as to whether or not the consumer actually saw at the ad. Well, it appears eyetracking company, Sticky has created a solution to do just that. By monitoring consumers gaze through a standard webcam, Sticky can quantitatively measure how an ad was viewed. The product has been tested on 350,000 consumers by the likes of P&G among others, and while privacy concerns abound, it could have serious implications for pricing models in the future.