“Subdomain or Subdirectory Name for a SEO Blog?–It depends!“
Some quick definitions of “Subdomain” and “Subdirectory”:
A subdomain is a completely different website (from the ‘main-domain’) and it looks like this, “http://subdomain.main-domain.com”.
*Note–For ease of clarification, I’ve used ‘main-domain’ instead of ’site-domain’ as the Top Level Domain (TLD): e.g. main-domain.com or Top-Level-Domain.com
The URL of a subdirectory looks like this: “http://main-domain.com/subdirectory.”
Search engines see subdirectory just that–subdirectory of the website’s domain. Basically, what that means is that the subdirectory belong to the site’s main domain or subdomain, which again is a different website from the ‘main-domain’.
So, if the main-domain has high page rank (PR), the page rank gets distribute throughout the subdirectories within the main-domain; but the subdomain does NOT, however, feel the PR love from the main-domain 
. This is, again, because the subdomain is a different website from the main-domain.
O.K. Now that we’ve gotten the subdomain/subdirectory definitions down, let’s go back to the question of whether a subdomain name or a subdirectory name is best fitted for your SEO blog.
To simply put, if you have have a main-domain site about cat, “www.cat-domain.com,” and you want to create a blog on “cat food,” then you should choose “cat-food” as a subdirectory for your SEO blog, “www.cat-domain.com/cat-food.” This is because “cat-food” is related to your ‘main’ website topic, so your subdirectory SEO blog will feel ‘more’ PR love from your ‘main-domain’.
On the other hand, if you want to create another site for “dog-food,” you should choose “dog-food” as a subdomain of the “cat-domain.com,” since “dog-food” has little relevance to your main-domain site, www.cat-domain.com.
And because a subdomain is a different website, you can actually have a subdirectory-blog in the subdomain (e.g. subdomain.main-domain.com/subdirectory-blog).
So, if you want an SEO blog out of the subdomain, you can have “luxury-dog-food” as a subdirectory name: “http://dog-food.cat-domain.com/luxury-dog-food”. And yes, if you have high PR for the subdomain “dog-food,” your SEO blog on “luxury-dog-food” also feels the PR love from your SUBDOMAIN, but not from your main “cat-domain.com”.
And that’s concluded my rambling on subdomain vs. subdirectory for an optimized SEO blog 
.
Anyway, to recap, if you have a blog topic (“cat-food”) that’s related to your main-domain website (“http://cat-domain.com”), for SEO purpose, you should choose the subdirectory route: cat-domain.com/cat-food. But if your blog is of different topic than your main-domain website (“dog-food”), you should choose “dog-food” as a subdomain name for your SEO blog: dog-food-blog.cat-domain.com.
O.K. Now, I really am finished rambling about the subdomain and subdirectory dilemma 
.
*Of course, you still need links (and other factors) to be able to rank in the SERP 
.
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One of the better descriptions on the difference between sub domain/directory I’ve read!
Reply to this comment »Its Nice, I’m looking for this post…
Reply to this comment »tks
hanks for this. very easy to understand although a complicated topic. much enjoyed, thanks!!
Reply to this comment »I think making a blog in domain subdirectory / subdomain is very helpful in getting traffic for main site. Blog gets frequent visitors and back links as compared to static sites and if your blog gets quality backlinks so as your main site will.
Reply to this comment »Nice topic “Subdomain or Subdirectory Name for a SEO Blog”.One of the better descriptions on the difference between sub domain/directory I’ve read!It is very easy to understand.Thanks.
Reply to this comment »Well I think a blog on a sub-domain is a good option and quite successful also.I have tried it many times and seem also and the results on it are good.
Reply to this comment »Thank you for such a useful article. The information presented will help everyone that reads it. Please continue to elaborate on this subject as I’m sure there will be more need for information on this in the future.nice way for me .
Reply to this comment »Nice post.If you throw your content into a subdirectory, usually the code is all in the same file storage space. That can make it much easier to find/edit/change code. It can also be easier to move code from one place to another. A subdomain, however, is often a domain name system (DNS) alias. Subdomains can be a little more difficult for a novice webmaster to set up, especially if words like “CNAME” don’t mean anything to you. Subdomains can be managed separately, which can be a joy (you can use DNS to decouple a subdomain if you want to migrate that part of your site) or a pain (it may be more of a hassle to juggle DNS setting instead of just using file commands to make or move directories).Thanks for share with us.
Reply to this comment »There are many traffic people on him site Now it’s possible people can now get best traffic and more improvement.
Reply to this comment »this is the article which provide us the right difference between subdomain and subdirectory name…thanks for providing i need this information…
Reply to this comment »great article…. it helped me out a lot with my website thanks
Reply to this comment »I love all the d-bags spamming their SEO websites here by making lame, meaningless comments. SEO experts are a joke.
Reply to this comment »Hey, I noticed that the first comment is dated 2007! Comments following are 2010 onwards. Anyways, its a nice attempt to explain the difference. I think I’ll apply this knowledge in way of having my blog related to my site in the subdirectory, and the general blog as the subdomain of my main domain. This way I have two blogs, on the same domain, though the subdomain is treated as a separate domain, but it follows the same alexa ranking as the main domain, as in my case. Thanks!
Reply to this comment »Well, in my opnion is the same…
Reply to this comment »I am concerned about this subject myself. I understood completely the importance on page rank juice for the main domain and not for the subdomain or its folders.
This is related to just one topic for each site, dogs and cats, but what about this:
If I have a domain name with my own name, and instead of buying and maintaining up to 10 different domains, I create one subdomain for each category where I could have blogs about playing guitar, affiliate marketing, computer programming and so on, would this affect my main domain ranks or even worse, can google decide that my main domain is being keyword stuffed and get bitch slapped?
Thanks,
Reply to this comment »Sergio
Hello,
I am searching for a blogging site where I can create my blog and then Main Domain name is hidden. Only the sub domain name and extension will be shown, such as onlinepokerjugar.tk
If any one have the knowledge about it then please let me inform by email.
Reply to this comment »Thanks.
mnalam@live.in
Hello,
I am searching for a blogging site where I can create my blog and then Main Domain name is hidden. Only the sub domain name and extension will be shown, such as abc.tk
If any one have the knowledge about it then please let me inform by email.
Reply to this comment »Thanks.
mnalam@live.in
Tips For New Bloggers,Seo Blogger templates, Seo Forum,Blogger Seo , Free Seo Tools, Free backlink
http://www.admin-seo.blogspot.com/
Reply to this comment »wow.. nicely written, this differentiates the big difference between them.
Reply to this comment »This is great advice. With sub-directories if a website has general content i.e. a store front, general topic site the subdirectory blog idea is a no go as opposed to a subdomain where any relevant content pertaining to generalized ideas would better benefit the main domain – dripping linkjuice down if the blog had a strong PR etc etc.
Reply to this comment »