You can click on the image to zoom in, but what you're basically looking at is a life size image of a person holding a Samsung smartphone. The sign invites you to get a free ebook (or song) by touching your Samsung Galaxy S III smartphone to the one shown on the sign.
I'm not completely conversant on the technical details, but as I understand it this late model Samsung Galaxy smartphone is equipped with a particular type of near field communications. You've probably heard about NFC in relation to being able to pay for stuff simply by waving a smartphone at an NFC scanner, but in this case Samsung is promoting their phone's ability to share content via NFC.
You may have seen one of the commercials, like this one. (At the end of that commercial you see the several SIII owners share a photo just by tapping the phones together.) The idea is pretty clever, and it just goes to show that as much as I might bash Samsung for their tablets, someone there can come up with an original idea.
This is definitely a trick which I would like to see ereaders adopt; it would be fun to share either the Nook and Kindle lendable ebooks simply by tapping 2 ereaders together, and I could also see some other practical uses (book clubs, ebook sales at cons, etc).
And given that the CEO of B&N has said that future Nook devices will get NFC chips, it seems more than likely that the Nook might get some feature similar to toe one shown in the video above. The again, Bill Lynch was thinking that NFC would be used in B&N stores to buy stuff, so perhaps they're not thinking far enough outside the box.
Has anyone seen these signs and gotten the ebook? I'd like to know what ebook they gave away.