Current mobile devices from Apple like the iPhone have a number of options for users to sync basic data, such as iPhone contacts, with Internet-based services. But the company is also said to be interested in offering a cloud-based streaming service for purchased iTunes content, like music and movies.
Store it later
Apple's application would allow such data to be stored locally, and synced later from anywhere with an Internet connection, rather than on a local network or via a USB cable.
The main idea is to ease the need for storage on the device, having an "extra" space for storage somewhere in the cloud. Given that data for just one HD movie can go up to the Gigabytes, the need for such extensions is very clear.
Besides the large files such as music or movies there are two other reasons why there is a need for both bandwidth and storage: Frequent updates of Apps and the constant flow of mails, web pages and social media messaging. While one data exchange is usually relatively small, the high number of interactions result in fast growing personal archives that no one wants to loose. These are drivers for cloud-storage, too.
Different concepts to synch multiple devices
The more tricky part though is, once these archives have to be synchronized not only between one device and a cloud, but for several devices a user might have. While synchronizing files is not easy even with a pair of destinations, the maintenance of data over several devices is quickly evolving into a highly complex task.
One option here is creating a central hub, that is serving as the "center" of a users data - updating and accepting changes that come in from interactions on the devices.
There is always a backup
From a users perspective this development is going into the right direction. One benefit could be that even if a device is lost, there is always a backup on the cloud. Another that data (e.g. music bought on a store) can never really disappear, because the cloud-based storage keeps an eye on the whole collection and library of the user.