Seems like Nintendo is going to go out of their way to make sure people know about the digital side of the 3DS. As if the SpotPass indications weren't enough, it also appears that content can be exchanged between 3DS units without you even knowing.

For example, if you have one system that is up-to-date with certain content while the other isn't, if those two 3DS' communicate, the up-to-date platform can send over apps to that other one. You might not know what Nintendo Video and Swapnote are, but when you interact with a friend you might also walk away with a few menu gifts to open!