From Bill Gerba's comments:

If I had to pick one concept to latch onto, it would be that the format is least annoying to consumers. After all, if a TV viewer or radio listener doesn't like a commercial, he can simply change the channel, and there's still a good chance that he'll change back after a while. Newspaper and magazine readers simply have to turn a page or two. But if a shopper gets really turned off by an in-store ad, she could just walk out, and that translates directly into lost sales revenue. Thus, while retailers can make huge gains by effectively marketing at retail, they also risk irritating shoppers and reducing customer loyalty. With this in mind, it's encouraging to learn that when it comes to digital signage, shoppers have indicated that they find ads on the screens to be unique, eye-catching and entertaining -- and less annoying than virtually any other medium out there today.

Link (Wirespring)

According to the sponsor,

The study was designed to gain deeper insight into how people engage with and respond to digital signage advertising. A few of the questions that the study answers are:

* How effective is advertising on digital signs?
* Is digital out-of-home media a better way to engage people who are busy and difficult to reach?
* How does digital signage advertising compare to other media?

Study is here.