When companies like Sticky use webcams to track users' eye movements when they're looking at advertisements, the end result is a heatmap. These heatmaps end up showing us a bit about ourselves, and how well certain ads work. There's a lot of work that goes into an advertisement, whether it's subliminal design, word placement, color, or what model to feature. By tracking eye movement, companies are going to become a lot more efficient at selling their products when they begin to understand where our eyes natural dart to, and for how long.
Here are some heatmaps provided by Sticky that reveal where our eyes go when presented with different kinds of ads and pictures (the redder the marking, the longer it was looked at):
Check out some more examples over at Business Insider.