What is a subdomain and how do they work?
A subdomain is a domain that is part of a larger domain. Some popular real life examples of subdomains that most of you will recognize are:
news.google.com
mail.yahoo.com
groups.google.com
Subdomains are enabled on almost all cPanel 10 and higher servers and you can create them through your control panel by clicking on the sub-domain icon if the option is active for your account. Most all paid hosting packages include some subdomains. More than a few offer unlimited sub-domains subject to your space and bandwidth allowances. The amount of included subdomains may vary from host to host. If your host does not offer a generous allowance of subdomains maybe you should start shopping for a new host.
Subdomains provide the ability to create a cleaner address than using just a directory. Currently subdomains are treated as separate entities by most of the search engines and do not dilute the focus of your primary domain. So you can also test a variety of concepts under one hosting account. Maybe you want to try blogging while keeping your real site on focus.
Maybe you want to use a subdomain to give one of you children or other family member their own web space. They can have their own FTP and be completely in charge of their space but they won't be able to damage your main site.
Article modified 11-18-2008.