Sony has just announced that in the next firmware update users will have the ability to save game data to the cloud. The feature will be called Online Saving and will be available in Firmware update 3.6.0. Online Saving will be available to PlayStation Plus subscribers only.
So rather than saving all of your game data to your hard drive or memory card you can opt to save it to Sony’s cloud. This way if you accidentally delete files off your hard drive or switch PlayStation’s you will still have them in the cloud.
Developers can opt out of Online Saving to be included in their games if they have concern with it being copied to the cloud.