Users are then responsible for registering a single account with a valid email address, credit card details along with a billing address (alternatively, a valid Paypal ID).

FORBES: European Courts Rule In Favor Of Consumers Reselling Downloaded Games

However, while investigating the breach over the weekend, Honan said he confirmed twice with Apple tech support that only two pieces of information are required to get access to an iCloud account: a billing address and the last four digits of the credit card associated with the account.

CNN: Heather Kelly,

Cardmembers already synced with Twitter for offers need to add a few more details, including their billing address, for product shipment.

ENGADGET: American Express cardholders can now buy goods by tweeting special hashtags

U.S. lenders report loan and credit-card activity to credit bureaus based on billing addresses, but that activity could stop if you change your credit-card accounts and loans to a foreign address.

WSJ: Getting Going: Managing Your Finances Abroad