What does iTunes backup when backing up an iPhone?

Answer 1

iTunes will back up the following information:

iPhone OS 1.1 and later

• Safari bookmarks, cookies, history, and currently open pages
• Map bookmarks, recent searches, and the current location displayed in Maps
• Application settings, preferences, and data
• Address Book and Address Book favorites
• Calendar accounts
• Wallpapers
• Notes
• Call history
• Mail accounts
• YouTube bookmarks
• SMS messages
• Saved suggestion corrections (these are saved automatically as you reject suggested corrections)
• Camera roll (photos and screen shots taken by the iPhone)
• Voicemail token (this is not the Voicemail password, but is used for validation when connecting. This is only restored to a phone with the same phone number on the SIM card.)
• Web clips
• Network settings (saved wifi spots, VPN settings, network preferences)
• Paired Bluetooth devices (which can only be used if restored to the same phone that did the backup)
• Keychain (this includes email account passwords, Wi-Fi passwords, and passwords you enter into websites and some other applications. The keychain can only be restored from backup to the same iPhone or iPod touch. If you are restoring to a new device, you will need to fill in these passwords again.)

With iPhone 2.0 and later

• Managed Configurations/Profiles
• List of External Sync Sources (Mobile Me, Exchange ActiveSync)
• Microsoft Exchange account configurations
• Nike + iPod saved workouts and settings
• App Store Application data (except the Application itself, its tmp and Caches folder).

New with iPhone 3.0

• Videos in camera roll
• Per app preferences allowing use of location services
• Offline web application cache/database
• Voice memos
• Autofill for web pages
• Trusted hosts that have certificates that cannot be verified
• Web sites approved to get the location of the device
• In-app purchases

New with iPhone 3.1

• Videos in the camera roll that are 2 GB or larger are not backed up.

Answer 2

It basically just saves a copy of all the data on your phone to your computer or to iCloud. If anything happens to your phone, and you need to format (delete everything) on the phone, you can easily restore all of your contacts, photos, apps, and other data. Hope this helped!