A business registration is a legal declaration of the structure a business entity intends to do business under, including Fictitous Name, Limited Liability Company, For Profit Corporation, Partnership, Non-Profit Corporation, and more.
The process of registering a business is simple in comparison to the benefits. According to the Small Business Administration, business owners register their business for reputation, tax advantages, business name protection, and liability protection. 
Business entities may register to operate under many business structures. A small business owner may register their business as an extension of themselves by filing a Fictitious Name registration. In addition to adding an air of legitimacy to the busienss, a Fictitous Name registration also provides the business owner with a limited level of business name protection because states do not permit more than one business to use a specific business name. However, the same business name may be registered to a business in another state.
A larger business or one that feels the need for liability protection may register to operate under one of the several types of corporate entities. In addition to legitimacy and the same limited name protection, a corporation enjoys additional tax advantages and provides the owner(s) with a level of liability protection.
Depending on the chosen business structure and state where the business is being registered, a business will register either with the county or state. All states require corporations to be registered at the state level, usually with the Secretary of State. While some states, such as Pennsylvania and Florida, require Fictitious Name registrations to be filed with the Secretary of State, in most states the County Clerk or Recorder maintains the registry of Fictitious Names.
An often cited point of confusion is that the address appearing on a business registration is not the same as the address where the business operates. The issue arises because there is no requirement that a business be located in the state in which the business is registered. J.P. Morgan Chase Bank is located at 270 Park Avenue, Midtown, Manhattan, New York City, New York.  However, the business registration for the corporation, as well as numerous subsidiaries, is filed in the State of Delaware.. This is because the address listed is that of the registered agent, not the business itself.
A registered agent is the person accepting responsiblilty to receive Service of Process documents. This may be the business owner, a lawyer representing the company, or a company that specializes in providing registered agent services.
Service of Process
In simple terms, the Service of Process address is where the business may be served legal documents filed with a court.
To mitigate confusion resulting from the Service of Process address on the business registration, some states record both the Service of Process address and the Primary Location of the business.
Many illegitimate businesses take advantage of the privacy afforded by some states. In combination with the rapidly expanding use of so-called "domain privacy" protection, determining who owns a business has never been more difficult.
If a stranger approached you offering to sell vitamins at a huge discount, but refused to give you their name, address, or any contact information beyond an email address, would you give them your credit card number? Would believe anything they tell you?
As a result of the methods to mask ones identity afforded by many states, domain registrars offering anonymity for a fee, and unscrupulous hosting facilities, it's very possible for criminal organizations and even foreign terrorists to operate what appears to be a perfectly legitimate business that exists to collect name, address, and credit details for black market resale or other future potential use.
It's not unreasonable to expect a business owner who wants your personal information to provide you with their own.