Just a quick note, I hated Shakespeare in school. Once I was done with school, it became a fascinating series of life lessons and twisted, timeless comedies.
In the battle of sub-folders vs. sub-domains I always fight in the name of sub-folders. Sub-folders have that magical power of creating a unique URL and inheriting the authority of the root domain. Sub-domains on the other hand, do not always inherit the authority or the full authority of their root-domains.
Think of it this way, a sub-domain is a child of the root-domain. The children get the benefit of having a parent but they are not the parent, they don’t have the same influence their parents do. This means that pages created by the child don’t have the inherent authority that a page created by the parent does.
Leaving behind that marvelous metaphor…
If you’re thinking about creating a sub-domain, odds are you can accomplish your goal with a sub-folder, and it will require less work to make it rank. However, sub-domains have their uses. But let me stress this point: USE SUB-FOLDERS. Thank you.
Do you feel that your ranking pages just don’t take up enough space in the SERPs? Feel that too much of your potential traffic is going to those pesky rank three and four pages? Then you need a sub-domain!
The ABCs of SERP Real Estate
A wonderful use of sub-domains is getting more SERP real estate. For paying the small price of not having inherent root-domain authority, sub-domains get the benefit of not being considered the same as the root-domain. This means they can rank in the SERPs alongside you’re already ranking pages without knocking them out of the game.
Imagine your home page, example.com, and your next most relevant page for the search: “examples”, example.com/examples-from-hell, are ranking first and second. That’s great. But let’s say that you want numbers three and four. You greedy marketer you…
Sub-domains are a great way to accomplish this. Go ahead and create “examples.examples.com.” Now get that sucker some content, a bit of PPC, a dash of Page Rank, maybe SEOmoz Link Juice…
And watch those puppies rank!
Welcome to the land of more traffic. No, not 405. Search traffic.
In conclusion… I had a teacher that said that at the end of every math lesson. I also had a teacher that said Winner, Winner, Chicken for Dinner. Or QED. It depended on if you had his class before or after lunch.
The moral of the story children, is that sub-domains have their uses. And they are nowhere near as many or as universally applicable as sub-folders. So when you think you want to use a sub-domain, you should use a sub-folder. Having a strong root domain that you can reliably add content to and see rank and get traffic to, is far better than maintaining multiple domains and having to decide which content goes where.
Apologies to the following for my terrible MS Paint butchering: