Miiverse:
Finally. the big social app is coming to the Nintendo 3DS. There will also be a web-based version of Miiverse and probably a smartphone version as well.
YouTube:
If you want another way to watch those funny cat videos on YouTube, you might be happy to know that a YouTube app will be available for the Nintendo 3DS. What we do not know yet is if it will include the 3D option.
Cross Nintendo Network ID:
This will combine the Wii U eShop service with the 3DS one allowing to use of the same funds and maybe even a cross-play feature. The only thing that can make this better is an account system so users can recover their games if their console breaks.