It’s easy to recognize the difference between sub-domains and sub-directories. When creating sub-domains, the new section name is placed immediately in front of the primary domain name, separated by a dot. So if my site is www.teammascots.com, I can create a sub-domain specific to one type of mascot by creating the url www.dogs.teammascots.com. Dogs is a sub-domain of teammascots.com.
By contrast, if I want to create a sub-directory for this same page, dogs would follow the primary url and look like this: www.teammascots.com/dogs.
(If you have no idea who Lee Corso is, you can learn more here.)
Here’s just a few reasons why sub-domains may be better suited to boost your site’s performance:
Google treats sub-domains similar to top level URLs. By contrast, a sub-directory creates another layer or level and is one level further removed from the main index or home page. Sub-directories enable one to create a more targeted top level and get the most out of your web design.
Creating a sub-domain allows you to use keyword triggers in your URL. Use your keyword toward the front of the URL. It may appear slightly more relevant to search engine crawlers while keeping the URL short.
You can avoid country code restrictions. Some countries require a company to have a presence within its borders before you can use the applicable country extension. Using a sub-domain, you can choose to address an audience or language demographic directly in the URL as opposed to having to use a country code. So instead of www.teammascots.ru, I’d opt for www.ru.teammascots.com. Problem solved and I didn’t have to outsource anything to a goat farmer in Kazakhstan.
CTR may be higher. It stands to reason that since folks read left to right, they’ll see the keyword they’re searching quicker in your URL. In theory, this should result in more clicks.
Sub-domains vs. sub-directories. Which is better for search engine optimization? In my humble opinion, there is a clear winner. Hey…where’d my UGA head go?