If you've got a Nintendo 3DS, you've probably already downloaded the new Swapnote app. And if you haven't, what are you waiting for? It's fun, and best of all, it's free!
I decided not to call this a review, because Swapnote isn't a game. It's just an updated 3DS version of PictoChat, a way to send messages back and forth between friends. You can send them either via SpotPass or StreetPass, although I was disappointed to learn that you can only StreetPass notes with people on your friend list, not strangers. Obviously a move to keep people from sending God knows what to complete strangers, but still sad.
Using the stylus, you can draw and write your notes, and you're allowed multiple pages for each message, although "ink" is limited. You can also add a level of depth by selecting a 3D pen instead of the regular one. There are multiple backgrounds to choose from, and you can even attach photos or sounds to your messages and let your friends download and keep them.
It's fun, but limited in scope. you can only have two levels of depth to your message, and you can only write in black. Although since Nintendo appears to be using SpotPass to update the backgrounds, I see no reason why other color inks couldn't be added at some point. Also, it's a little frustrating that Swapnote limits your abilities in the beginning, forcing you to send some lame 2D messages before giving you the 3D pen and the ability to add attachments as it teaches you all the things you can do. And while I was initially irritated that you have to spend Nintendo Coins to get special backgrounds and attach things, I guess in the end it's not really that bad, because honestly, aside from Find Mii, what else can you use them for?
So just head on over to the eShop and download Swapnote for free, and get swapping! Now, I just need more friends with 3DSes!