Swapnote

Swapnote lets you create handwritten notes and then share those notes
with other Swapnote users on your friend list via the StreetPass
features. Nintendo might even send notes to you too! As your note
collection grows and you spend Play Coins, you’ll unlock new features
and be able to personalize messages even further by changing stationery
patterns, attaching photos and sound recordings, writing and drawing in
3D, and more. You’ll even be able to surprise your friends with secret
notes that they can only open on a certain date! Passing handwritten
notes to your friends is a breeze, regardless of whether they’re sitting
across the room...or across the world!

Please note that the SpotPass feature of Swapnote (the ability to
send notes to friends over the Internet) has been stopped as of October
31, 2013. We greatly appreciate your understanding. Learn
more >