I think what you'll see is an extension of what's done in the calendar app in iOS 4. That is, the calendar database is a specialized database just for calendar,

I think what you'll see is an extension of what's done in the calendar app in iOS 4. That is, the calendar database is a specialized database just for calendar, other apps can access and modify it, and it syncs with the cloud and all your devices. I think you will see the same thing for many other types of databases, but they will all be dependent on type. The databases already there are music, contacts, notes, PDFs in iBook, epubs in iBooks. I think you'll see the full ability to access and modify those databases, and full cloud syncing of them as well. But, they will still be different and separated by file type or task.