Apple ID is Apple's user identification system intended to be a single sign on for users of Apple services, hardware and software.
The following products and services rely on an Apple ID for identification:
- iTunes Store on Mac, Windows and iOS. This includes the iBooks Store (iOS only); iTunes Music, Podcast, Movie plus TV and iTunes U stores; as well as the iOS App store
- Mac App Store
- Apple Store iOS app for purchasing
- Apple Online Store
- iPhoto and Aperture photo and book ordering services
- Registering for various Apple Developer Programs
- Registering Apple products in their service and warranty database
- Obtaining services such as warranty support, Apple Care, genius bar appointments, One to One training, Joint Venture training and support.
The Apple ID system does allow for financial transactions to be processed so in addition to serving as a user identification and authentication service, it also serves as a micropayment system for electronic commerce and ordering physical goods and services from Apple.