Domains are an easier more efficient way for users to navigate the internet and for website owners who conduct ecommerce to create a brand and identity. Domain names, like mysite.com, or mybusiness.com, are coupled to an IP address (the IP address represents a physical location on the Internet for the search engines). An IP consists of many numbers which are often too long and too difficult to remember and not user friendly. The Internet Corporation for Assigned Names and Numbers (ICANN) is the foremost body that organizes the links between IP addresses and domain names throughout the Internet, so that you can find a Web site by simply entering a user friendly domain name (which is much easier to remember) instead of an IP address into your Web browser.
A domain is made up of two essential parts, a top-level and a second-level domain. A top-level domain (TLD), referred to as the domain extension, is the portion of a domain name located to the right of the dot (mysite.com). The most common domain extensions are .COM, .NET, and .ORG. Some the other more popular extensions are .WS, .INFO, .BIZ, and .NAME. These common extensions have certain guidelines you must follow in order to qualify for them, but are usually available to any anyone, anywhere in the world.
In addition to the more common top-level domains there's what is known as restricted or (rTLD's). They have extensions like .AERO, .BIZ, .EDU, .MIL, .MUSEUM, and, .NAME, requiring that the registrants represent a certain type of organization, entity or to belong to a certain community. For example, the .NAME domain extension is reserved for individuals, while .EDU is reserved for educational entities and so on.
Country-code TLDs (ccTLDs) are for Web sites and registrants located in a particular geographic location, and want users to be aware of their location such as .BZ (Belize), .CA (Canada), .DK (Denmark), .EC (Ecuador), .IE (Republic of Ireland), .UK (United Kingdom), .US (United States).
The portion of a domain name found to the left side of the dot (mysite.com) is referred to as the second-level domain (SLD) name. The second-level domain name is the "comprehensible" part of the address and refers to the organization, group, or entity behind the Internet address. This portion of the Domain is what will identify and distinguish you from other entities on the internet. Second-level domain names have to be "distinctive" on the Internet and registered with an ICANN-accredited registrar.
What is a Whois listing?
The Whois record contains very important information associated with a particular domain name. It has facts such as its creation date and expiration date; the name of the registrar of record, and various contact information such as (administrative, technical, etc.). Whois records are collected at the time the domain name is registered and is a matter of public information. The Whois documentation appears whenever a person conducts a Whois search on a particular domain name to find out who owns the domain in question. However, most domain registrars offer private registration for a small fee. This will keep any private information that you don't want to be known publicly from being displayed in the Whois database.