Coming from the recent Iwata Asks...
Shimamura: Yes. Usually when you download software, you go to the Nintendo eShop, pay, and then download.
Shimamura: That's incredibly easy, but there are a certain number of people who find that to be a pain. So this time, in order to reduce that hassle, if your Wii U is connected to the internet and you have at least 1.3 gigabytes of free space, Wii Sports Club comes in to your Wii U automatically through SpotPass.
Iwata: I believe those who updated their Wii U console the other day received a message upon opening their system again asking if they would like to automatically receive content via SpotPass. If you answered "OK" and have 1.3 gigabytes or more of free space, Wii Sports Club will be delivered automatically.