What Is a Subdomain?
A subdomain is an addition to the beginning of a website's main domain name. The subdomain goes before the root domain, separated by a dot. For example:
Main Domain: www.mysite.com
Subdomain: blog.mysite.com
In this case, "blog" is the subdomain name that prefixes the root domain "mysite.com". So the full subdomain URL is blog.mysite.com.
It's like creating a smaller mini-website that lives inside your main site.
You can create multiple subdomains for different sections like: shop.mysite.com, support.mysite.com etc.
Why Use Subdomains?
Organize Your Content: One of the main benefits of subdomains is they allow you to neatly separate and categorize different content areas on your website. Instead of having everything jumbled together on your root domain (www.mysite.com), you can compartmentalize using subdomains:
www.mysite.com - Main website
blog.mysite.com - Blog section
shop.mysite.com - Online store etc.
This makes it much easier for visitors to find and navigate to the specific sections they want without digging through your whole site.
Unique Branding & Customization: With subdomains, you can make each section look and feel totally unique if desired. Your main site could have one design and branding, while the blog.mysite.com subdomain has a distinct look, colour scheme, features etc.
This level of customization for different areas is trickier when just using subfolders within the root domain.
Subdomains make it easier to give personalized branding and functionality to logically separated sections.
Testing Playground: Subdomains provide a safe playground for testing new ideas before rolling them out across your entire main website. You can experiment with a new blog, online store, tools or whatever on a subdomain first.
If the subdomain tests well, you can integrate it more prominently. If not, you can simply delete the subdomain with minimal impact on your primary site.
Subdomains vs Subfolders
It's important to understand that subdomains are treated differently than subfolders like:
www.mysite.com/blog
Subfolders stay within and are considered part of the root domain. But subdomains are technically treated as separate entities, almost like distinctly new websites under your main domain's umbrella.
This separation allows the customization flexibility mentioned earlier. However, it also means subdomains don't automatically inherit things like the page authority, search rankings, settings etc. from the root domain right away.
Easy or Advanced Implementation
On a basic level, creating and setting up subdomains is usually very easy. Most domain hosting providers allow you to quickly add new subdomains with just a few clicks in the settings panel.
However, subdomains can also potentially get more advanced. You can have unique DNS settings, hosting arrangements, code bases, and more configured for individual subdomains if needed for more complex setups.
Conclusion
Subdomains provide powerful flexibility to expand your web presence by neatly categorizing different areas under your main domain's umbrella.
Each subdomain can have unique branding and features and even be a fully separate website experience if desired.