well like i said earlier the first thing that came to my mind was websites like groupon and living social. Also, I think websites like Zappos or Newegg that are well known in certain circles but perhaps not as ubiquitously as they would like could really benefit from your services. For example, I know that in the Newark, NJ airport there are zappos ads in every security bin. I'm sure they would love to see a heatmap of how traffic from that area has changed since they implemented that ad. The heatmaps provide a simple and easy to understand visual aid that can really help explain whether changes have come about.