Subdomains or Subfolders : Which are Better for SEO?

May 6th, 2008 by Loren Baker, Editor | 19 Comments

An SEJ Reader send in the following question :

Subdomains or Subfolders? What’s better for a blog/forum/etc: a subdomain (eg. http://jobs.searchenginejournal.com/) or subfolder (eg. http://www.seomoz.org/blog/)?

Subdomains and subfolders both have their advantages, especially when setting up blogs.

For blogs, I prefer a subfolder (http://www.seomoz.org/blog/) because the link juice which is sent to that blog is going to be naturally distributed to that main domain, and other subfolders under the domain.

Futhermore, the forum/blog will default logo, home page and other links back to the subfolder. If you set this up with a subdomain, by default, the links in the forum/blog itself will all point back to the subdomain. So, with a subfolder, both the inbound and internal linking structure favor the entire site.

With a subdomain, the forum or blog will be listed as a separate entity in the Google search results, which is good for owning the results and one’s reputation management. However, Google and other engines will generally not list more than two of these subdomains in the search results, unless those subdomains can prove to Google that they are independent and relevant entities.

I would like to reference Vanessa Fox, an ex-Googler and contributor to Search Engine Land :

Google is no longer treating subdomains (blog.widgets.com versus widgets.com) independently, instead attaching some association between them. The ranking algorithms have been tweaked so that pages from multiple subdomains have a much higher relevance bar to clear in order to be shown.

It’s not that the “two page limit” now means from any domain and its associated subdomains in total. It’s simply a bit harder than it used to be for multiple subdomains to rank in a set of 10 results. If multiple subdomains are highly relevant for a query, it’s still possible for all of them to rank well.

Home Depot is one site which has cleared the relevancy bar at Google with subdomains at HomeDepot.com that are actually marketed as individual sites. Take careers.homedepot.com and look into its backlinks, even if this subdomain was on a whole different domain, like HomeDepotJobs.com, it would probably rank just as highly.

So, in conclusion, if you’d like to build the equity of one web site or entity, I suggest using a subfolder. If you’d like to build an entire new entity with its own equity, launch a subdomain.

Your thoughts, comments and concerns are well appreciated.

Comments

19 responses so far ↓

Jaan Kanellis on May 6, 2008 at 9:52 am

According to Google they are treated the same.
Raf on May 6, 2008 at 10:24 am

I am not sure about google, but just to look from the logical point of view. If you have a top level domain that is ranked high you should add a subfolder to make use of it. If you add a subdomain , the rank is started from zero. It’s like having two separate domains. Somebody correct me if I’m wrong. Cheers!
Edward Beckett on May 6, 2008 at 10:33 am

http://www.mattcutts.com/blog/subdomains-and-subdirectories/

And I quote the Cutts …

“My personal preference on subdomains vs. subdirectories is that I usually prefer the convenience of subdirectories for most of my content. A subdomain can be useful to separate out content that is completely different. Google uses subdomains for distinct products such news.google.com or maps.google.com, for example. … “
Linda Bustos on May 6, 2008 at 11:06 am

Gotta agree with jaan k here.

Google did announce it will treat subdomains like subfolders to combat the spam techniques and ranking effects of, say, ebay subdomains.

http://www.seroundtable.com/archives/015621.html

However, I haven’t seen this in practice yet, I still see multiple subdomains appearing from ebay for certain searches. Perhaps it’s a rollout.

Now, if subdomains and subfolders are treated the same, then link juice *should* also flow between them.

One benefit of subfolders, though, is you don’t have to add and verify them separately in Google Webmaster Tools - which, if you have a lot of subdomains (country/language/product etc) can save you a bit of time.
Loren Baker, Editor on May 6, 2008 at 11:08 am

“However, I haven’t seen this in practice yet, I still see multiple subdomains appearing from ebay for certain searches. Perhaps it’s a rollout.”

Or perhaps it’s because eBay is more of an authority than other sites which used subdomains to spam Google, no?
Mercy on May 6, 2008 at 11:14 am

I personally prefer having a sub folder forblog or forum. Its easier to maintain and as Loren said the Link Juice will pass equally to the whole domain.
Gregor Spowart on May 6, 2008 at 11:16 am

One other thing to consider is that when you create a sitemap (certainly using the tool I do), it’s easier to build the entire sitemap if your blog is in a subdomain rather than a subdirectory.

Which is why I’ve just spent some time today getting my blogging software to move from a subdomain to a subfolder. It was a total pain!

Timely article though - thanks for this.
Kiowa Jackson on May 6, 2008 at 12:01 pm

@ Linda Bustos

Thanks for the link, I was looking for that…
Bjorn Solstad - Devenia SEO Labs on May 6, 2008 at 2:59 pm

It should not be to hard to setup a test environment and measure the results from both variations. I will put it in my todo-list of experiments to perform.
CVOS man on May 6, 2008 at 7:15 pm

if you’d like to build the equity of one web site or entity, I suggest using a subfolder. If you’d like to build an entire new entity with its own equity, launch a subdomain.

Well stated. It is much more cumbersome for the average user to try to navigate subdomains. For example Yahoo sites (YSM im looking at you) is much more confusing to navigate than Google (adwords, mail, maps etc.)
Steve Patterson on May 6, 2008 at 9:20 pm

Thanks for sharing this.
My blog is done as a subdomain.
To me doing it as a subdomain helps keep it seperate from the main site.
I have several subdomains that I do and each have different topics etc.
Prestamos on May 7, 2008 at 12:37 am

folder are the best choice if you want to rank easy based on your incoming links to your domain.
Edward Beckett on May 7, 2008 at 12:56 am

@Prestamos …

Can you express a P.O.C. for that … ?
SEO Checklist on May 7, 2008 at 2:33 am

When you try to rank as many subdomains in the SERP’s isn’t that considered as spamming the SERP’s?
Edward Beckett on May 7, 2008 at 3:00 am

@Bjorn

echo: SEO Checklist

append TODO …
Pisos-web on May 7, 2008 at 4:27 am

Completing Linda Bustos’ input, Google Webmasters Tools reports links from one subdomain to another in the same domain as external links.

Not that I think that those external links count at all, at least not the way links from external domains do. I agree that subdomains are only pertinent when they contain different content.
Ann Smarty on May 7, 2008 at 4:38 am

Google (Matt) gave a vague explanation as for that change:

“This change doesn’t apply across the board; if a particular domain is really relevant, we may still return several results from that domain.”

This “high relevance” may apply to any case.

But honestly, I tend to see these slight changes take place; and I guess G will be getting even better at telling which subdomains deserve a separate position in SERPs and which don’t. (So if you aim at more than one SERP position, you’ll need several domains - subdomains won’t help a lot; so in this perspective, there’s no point in subdomains).

Besides (@Linda), by ‘treating subdomains as subfolders’ the post you are citing means rankings, and not link juice. So, no, not completely the same.

So the main question is, what’s better for link juice. On the one hand, subdirectories grow the link authority of the domain. On the other hand, like Vinny said, a domain is able to give more link weight to a subdomain than to a subfolder:

“I think you get more link weight back from a subdomain. For instance services.performancing.com gets oodles of links back from the main blog site of performancing.com. I imagine their rankings for their services page would be a lot less if the links from the main site pointed to a subfolder instead of a sub-domain.”

So what’s better from the linking point of view?
next STEPH on May 7, 2008 at 4:28 pm

Why not have the best of both worlds? Start off with a subfolder and when necessary have the subdomain URL forward to the subfolder?
Michael Aulia on May 8, 2008 at 6:42 pm

Hi guys, I currently have my blog under a sub-folder (www.michaelaulia.com/blogs/) and have all backlinks go to it (/blogs/) instead of the root domain.

Is this a good practice? My PR hasn’t get updated for months..unless if I’m doing something wrong here…