iCloud Apps Sync
iCloud stores your music, photos, apps, calendars, documents, and more. And wirelessly pushes them to all your devices automatically. It's the easiest way to manage your content. The iCloud apps sync function includes 3 parts, they are:
Former MobileMe Sync
The former MobileMe services: Contacts, Calendar and Mail.
All completely re-architected and rewritten to work seamlessly with iCloud. Users can share calendars with friends and family, and the ad-free push Mail account is hosted at me.com. Your inbox and mailboxes are kept up-to-date across all your iOS devices and computers. （Related: How to Sync Contacts from iPhone to iCloud.)
iCloud App Store Sync
App Store lists the purchase history of all your app downloads so it's easy to re-download them on a different device. With iCloud app store sync, you can transfer apps among iPad, iPhone, iPod touch easily and fast.
iCloud iBooks Sync
iBooks does the same with all the iBooks you bought and it'll even sync your bookmarks. With iBooks sync, you can read them same book purchased from iBookstore on iPad, iPhone, iPod touch.
iCloud Backup Sync
Backup backs up all the important stuff of your iPhone (pictures, settings, music, apps, app data) daily. With iCloud backup sync, you can backup the files including music, videos, photos, and so on from iOS devices such iPad 2, iPod touch to iCloud, so you don't need to worry about all stuff on your devices may be lost some day.
iCloud is so much more than a hard drive in the sky. I's the effortless way to access just about everything on all your devices. iCloud stores your content so i's always accessible from your iPad, iPhone, iPod touch, Mac, or PC.
Related Links: How to Backup DVD to iCloud