If you’re wondering what a subdomain could be, here is a simple analogy that can help to explain the term. Suppose you’re looking to visit the CNN website, you’ll likely type something that looks like www.cnn.com. This is simply what is referred to as a subdomain.
However, there are several names that different webmasters use in place of the term “subdomain” although all mean the same. For example, you will hear some people refer to it as a “canonical” while for others it’s a “third-level domain”. With “third-level domain”, the logic is that with the “.com” being the top-level domain and “cnn” being the second-level domain, the “www” thus becomes the third-level domain.
For some countries such as the UK, you may find top-level domains that consist of two “parts”. For example, you’re likely to find “co.uk” and “org.uk”.
Going by this, a domain name that appears as “mycompany.co.uk” is termed as a “real domain” and thus not a subdomain of the “.co.uk” extension. In such a case, what would qualify to be a subdomain would be something like “sales.mycompany.co.uk”.
Why Subdomains are Sometimes Referred to as Machine Names
In some cases, subdomains are used to identify particular computers with each having been allocated a unique IP address. When that happens, you may find these subdomain names being referred to as “machine names”.
A good example of this is where you find a company operating two servers, one labeled as “accounting.thecompany.com” while the other is labeled as “marketing.thecompany.com”. This way, these two computers are meant to serve separate departments with each carrying its unique information.
Subdomains For Load Balancing
In cases where a website is extremely busy, developers may formulate a setup whereby subdomains are capable of identifying different computers even if they contain same information. For example, if a visitor types www.thatsite.com, the system chooses the computer that’s available at that time using a load balancing mechanism. In such a case, the visitor will be directed to one of the computers labeled something like “www2.thatsite.com” or “www8.thatsite.com”.
Subdomains For More Organized Information
Subdomains are sometimes used to organize information in a particular website. For example, some eCommerce sites organize their sites using subdomains such as “books.ourshop.com” or “utensils.ourshop.com”. This way, they are able to put related information together and which helps them achieve more organization. The same technique is also used by huge sites such as “About.com.”
For example, if you visit the About.com website, you will hardly fail to notice their prevalent use of subdomains which largely depends on the topics they cover. A good example is “autorepair.about.com” or “food.about.com”. However, you could ask, “why can’t they use about.com/autorepair or about.com/food?” Well, the logic behind it is that the use of subdomain makes it easier for the developers to move any of their topics to a dedicated computer once that topic gains more traffic. While this is important to big sites such as About.com that have very high scalability potential, normal sites may consider to just use subdirectories as they may not need numerous subdomains that are often included in highly advanced hosting packages.
Need to add a subdomain? It’s free
Yes, you heard that right. Often, your registrar will give you the independence to create as many subdomains as you wish. This, therefore, means that you do not need to pay anything whenever you need to create a subdomain.
Some web hosting providers will charge you if you request them to create the subdomains for you. Essentially, the fee you pay is not meant to cater for the “registration”. Rather, it’s for the service rendered and perhaps for the additional resources consumed such as the disk space.
While this is important to big sites such as About.com that have very high scalability potential, normal sites may consider to just use subdirectories as they may not need numerous subdomains that are often included in highly advanced hosting packages.