Which Is Best For Development? Directory Structure Or Sub-Domain?

Every now and again people ask one of the old classics in this thing of ours; directory structure or sub-domain. Which is best?

The conventional thinking is usually that if it is substantially a different site/element, use a sub-domain. But is this a fast and hard rule? Not really. Personally I am more inclined to consider it if there are language issues (or other geo-targeting issues) or a definitive break in focus.

As just a quick highlight it should be noted that one can train ol Google to understand structural elements… some site-links;

Main Blog – this one uses some site wide ‘popular post‘ links and includes the Dojo module link (SEO Training);

Site Links Fire Horse Trail

Dojo – is generally also using the more prominent, site wide, navigation links;

Site Links Huomah.com

Given the site links it does seem Google most certainly understands the distinct differences between the blog and the training module. We can see the same when looking at say, the ‘Moz;

Site Links Moz

And actually, you can re-produce this with more than a few brand related searches on the Moz (such as LinkScape). Taking the next obvious leap, how about Aaron? He has the site links on the brand search, but the sub-domains are 50/50 ;

Site Links SEO Book

Although, it is interesting that with his sub-domains he can get more listings in a give brand SERP. It would be an interesting usability study to see what users preferred in such situations (ie; saturation or site links). And I would look aroud the market to get an idea (as always) of how the SERPs are with top brands/authority sites. Either way, I simply wanted to highlight a few SERP elements here, show a few architectural approaches. I leave it to you to dig in deeper :0)

The main thing is that a directory structure can often perform much the same as a seperate TLD or sub-domain. 

What can you do with it?

Looking at a bunch of other sites, and SERPs, it is down to not only the structural layout of a site, but also the distribution of links within the segments and how the brand structure is organized. This is a concept to consider when building a site and making the decision of how to develop. Many times people tend to assume that a sub-directory structure is the way to go, which is not always the case. There are some inherent internal linking opportunities (and authority building) that exist in a directory structure that aren’t always as responsive in a sub-domain approach.

Now, this isn’t something I’d go changing a site around to do. You know, ‘task ROI‘ and all that. At the end of the day time should be spent on creating authority for any given area of the site. But if you are in the process of re-adapting the information architecture of the site, don’t be quick to jump on SD structures.

It would be something to put into the tool box and decide on a case-by-case basis what value can be had with either approach. I just thought it worth mentioning as a few folks were surprised to see this behaviour in Google… so it might interest others.

Ciao… cya in the SERPs


By David Harry

David Harry is the President of Reliable SEO and has been building and marketing websites since 1998. He can be found writing about search and internet marketing on the Fire Horse Trail and is the author of the SEO Handbook series. http://www.reliable-seo.com http://www.huomah.com http://www.the-seo-handbook

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