Domain Names simply explained

Domain names were created because, without them, the Internet’s addressing system really does not work very well. While each computer on the Internet has its own IP (Internet Protocol) address, these are just a string of numbers separated by a dot, such as 165.166.2. Remembering the IP addresses of web sites in this way is virtually impossible, so to make things easier, the domain name system was created.

Domain names can be described as the address of the Internet in humanly readable form. Each domain name is unique in its own way, but all have three common elements:

  • A top level domain (TLD), known sometimes as an extension or domain suffix;
  • A domain name (or IP address); and
  • An optimal subdomain


The top level domain is the formal name for the suffix that appears at the end of a domain name. In the early days of the Internet, seven generic top-level domains were created – .com, .org, .net, .int. .edu,.gov, and .mil – and these continue to have great authority on the web now, although there are actually over 1,000 possible TLDs from which to choose.


One example of this is: and

Then there are the country- code TLDs. Nearly every country has its own two letter TLD name – such as the United States (.us) and the United Kingdom# (.uk). For these TLDs special rules apply, such as who can authorise and issue them, the renewal dates and procedures for transferring them to another owner.

Domain names are the second level of a domain’s hierarchy. Domain names on a specific TLD (called a root domain) are bought and obtained from a register. They can be regarded as representing the unique location of a website, as with the following examples: (where bp is the domain name) (again shell is the domain name)

Internet search engines use the keywords in domain names, but gone are the days when internet marketers could stuff keywords in to their domain names and hope to rank highly on Google! Their algorithms are now specifically designed to spot such tactics and to penalise them accordingly.

The term root domain typically refers to the combination of a unique domain name and a top level domain to form a complete website address. The root domain of a website is the highest page in the site hierarchy – usually the homepage. Whilst individual pages or subdomains can be built off the root domain in theory, to be part of the website each page url must include the same root domain.

An example of a root domain is:

All the pages on a single website have the same root domain. No website can have the same root domain as another.

Subdomains are the third level of a domain’s hierarchy, and are part of a larger top level domain.

The most common subdomain is www, as in the following example: where the www part is the subdomain.

However, with the following site, there is no sub-domain:

The problem is that as the Internet has exploded, there are literally millions of domains out there, and for internet marketers looking to undertake market research, create customer lists and identify potential customers, the task has got too big for humans to undertake alone. For example, according to the Q4 2016 Domain Name Industry Brief, there are approximately 329 MM domain names registered in ccTLDS (country TLDS), gTLD (generic TLDS), and new GTLD zones (new domain strings which are being created by ICANN – the Internet Corporation for Assigned Names, a non-profit which essentially regulates the naming convention and boundaries of the Internet).

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