Along with Contacts, Calendars and Mail syncing, iCloud also includes three apps that'll keep all your iOS devices synced through the cloud. They're called App Store, iBooks and Backup and they're all pretty self explanatory.
App Store lists the purchase history of all your app downloads so it's easy to re-download them on a different device. iBooks does the same with all the iBooks you bought and it'll even sync your bookmarks. And finally, Backup backs up all the important stuff of your iPhone (pictures, settings, music, apps, app data) daily. That way when you get a fresh iPhone, you simply log in and everything shows up. It's syncing without the cord now.
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