Specifically, the contents that pulled into users’ device by the new Downloads For You feature are based on their viewing habits. This does not mean that Netflix has free reign over the storage space of the device though.
As part of the activation process, users also need to set the storage limit for the feature which ranges from 1GB to 5GB. Just like the original Smart Downloads, Downloads For You only works through a Wi-Fi connection. The new Download For You feature is now being deployed to Android devices throughout the world. As for iOS users, they have to wait for Netflix to test it on the platform sometime soon though. (Source: Netflix [1][2].)