What Is iCloud.
What Is iCloud For: Apps, Music, Contacts, Books, Photo Stream, Notes. iCloud stores your contacts, calendars, apps, music, photos and more, and wirelessly pushes them to your devices with iOS 6 installed, and to your computers. iCloud is integrated with your apps, so everything happens automatically.

For example, if you buy a song in iTunes on a Mac or Windows computer, it appears on your iPod touch and iPad. When you snap a photo on your iPhone it’s automatically sent to your iPad. You can start creating a Pages document on your iPhone, and put the finishing touches on it from your iPad. There’s no need to dock your iOS device or sync it to your computer.
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