The Lagoon TechMy little blog in Cyberspace.

In this blog post, I am going to give a brief explanation of what sub-directories and sub-domains are in the context of websites. Which one is the best for a website? Well that is not an easy question to answer, however I’ll give my opinion (and experience) and let you make the final decision.

Simply put, a sub-directory is a directory right off a domain name (e.g., www.example.com/subdirectory).

A sub-domain is a little different. They look like this:  mywebsite.example.com

First you must understand that in my experience, both sub-directories and sub-domains are not treated the same way by search engines (e.g., Google, Bing).

If I put something on www.example.com/myfiles, Google will see the “myfiles” part as a part of the main www.example.com domain.

However Google, from my experience, will treat a sub-domain as if it were separate from your main domain, and will not count myfiles.example.com as a part of your original example.com ranking. 

To recap:  Sub-directories are seen by search engines as a part of your main domain (e.g., www.example.com/myfiles  goes with  www.example.com).

Sub-domains are seen by search engines as separate from your main domain (e.g., myfiles.example.com  does not go with  www.example.com).

Do you see the difference?  So which is better for a website you ask?

Well in my opinion:

Use a sub-directory when you want to make sure that your main domain (e.g., www.example.com) gets more attention from search engines, and in turn, hopefully a better search engine ranking.

Use a sub-domain when you either do not care about adding value to your main website and/or when you have a website or service so different from your main website, that you want search engines to treat it as if it were separate from your main domain.