"Dun and Bradstreet" is a proprietary "business number". For consumer protection, it would be nice if every business had a unique government-assigned number and all ads be required to give that number. The government requires every citizen to have a unique number in most societies, so why not businesses also?
Most (if not almost all) juridictions register their businesses in a process that assigns a number. Furthermore, all businesses can be accessed via many different types of numbers. A few examples:
I believe the real issue, therefore, becomes; What is the intended use of a Business Identifier Key (since that will determine the nature of any 'atomic' Keys that should be assigned and any Composite Keys that should be created from the Atomic ones). -- HansWobbe.
Law enforcement, for one. You need to know who to investigate or who to sue. "Bob's Lead Toys, Co." could be anywhere.
Enforcement suggests employment of Observation and Surveilance while encouraging compliance with laws and regulations via sanctions, fines, and detentions.
See also: ArePhysicalPostalAddressesArchaic