WHAT IS A DOMAIN?

WHY DO I NEED A DOMAIN?
A Domain Name is a textual version of an IP address, the number that points to a particular Web site. Each domain on the internet consists of numbers, but it would be very confusing if you had to remember such long combinations of numbers. For example, the number 66.218.71.198 is the IP-address for yahoo.com. 
Without domain names each and every Web site would have to be recalled by a number like this, similar to the telephone system, but much more difficult to remember! For this reasons domain names were introduced, and have made navigation on the net much simpler!
A Domain name is like a postal address. It lead to a particular destination. A Domain name is a name typed into your browsers address bar or clicked on from any web site, displaying the web site that the domain name is associated with, having a web site without a domain name - how is anyone going to find you without an address?
Every domain name has an extension or TLD (top level domain).
An example of a Top Level Domain is ".com" or ".net" or ".org".
An example of an entire domain name is "www.google.com"
Every domain name is unique. There can never be two domain names the same. This is why it is important to register your domain before anyone else does. Even if you do not intend to implement your web site in the nearest future, it is highly recommended to register your domain name to avoid it being taken.