My idea is simple. With connected e-ink displays for the price of items in physical stores. I thought why not implement an easy way for the customer to make a choice based on the popularity. Similar to the way you choose software based on the number of downloads or ranking here you could see what items are popular with some number representing the popularity. I think this could work for a lot of groups of items. The idea is to get information like the combined preference of a lot of customers to the individual customer in an easy way.
I think this additional information could convince you to buy a kind of product you might not have tried otherwise. Now that you see that it is popular.