Maybe you want to display on your shop or anywhere a counter of the number of fans you have on your Facebook page.
There is connected devices that allow users to do that (like Smiirl) but they are quite expensive. The idea is to do here something simpler: create a webpage that will display the number of likes/ fan on your facebook page that will then be displayed in full screen in a tablet.
Doing that was quite easy a few years ago but security policies did evolve and it is a bit more challenging now. I did find a way to do that. It is a live counter that will automatically update every 20 seconds.