The Nintendo Switch could let you transfer save data across multiple consoles. Since the Nintendo Switch launch earlier in the year, it’s been a much requested feature as it would allow you to continue your progress in a game on another console without having to start from the beginning.
According to the Nintendo Switch software development kit (SDK) which has been leaked, you can expect to transfer save data from your games as well as a Guest Login function in the future.
“In the future, we plan to provide a feature to transfer account save data among multiple consoles. As a result, there is the possibility that user accounts with uninitialized account save data will be added. Note that your design must work without issue, even in this case,” notes from the Nintendo Switch SDK read.
As for the Guest Login feature, this is what you can expect according to Nintendo’s documentation:
“We are considering a feature in the future (tentative name: Guest Login) to access existing network service account information without linking to a user account. This feature would allow temporary access to the network service account linked to the Nintendo Account by logging in to the Nintendo Account within the application. This feature would, for example, make it possible to upload a character you have raised as online data and then use that data on a friend's NX (without creating a user account).”
While this leak won’t ensure any use outside of Nintendo’s intended use for the Switch just yet, it could be important towards understanding how running software on the Switch works, which could in turn result in homebrew applications for the device, much like we've seen for the Nintendo Wii, 3DS, and Wii U.