If you’re planning to build a new website, do a major migration, or redesign a site, one of the first questions you might have is how to structure your site for search engine optimization. Given the widespread debate over using subdomains vs. subdirectories, you might be unsure which site structure you should choose and how that choice will impact your SEO. Let’s take a closer look at subdomain vs. subdirectory pros and cons before I dive into our time-tested recommendations.
Site Structure & SEO
Site structure relates to how you organize information on your website to make it available to visitors and search engines. Whether it’s mapped out with intention or just “happens” as you add content, your website’s structure can either support or frustrate the user experience. A carefully planned site structure will help users find their way to important content and offerings, and additionally, will improve your SEO.
The more clarity in your content hierarchy and how pages relate to each other, the easier it will be for Google to index your site — directly impacting how your pages will perform in search. Beyond being easier to index, a well-structured site offers more internal linking opportunities — another significant ranking factor.
What is a Subdomain vs. Subdirectory?
By far the most common question I get from people who are considering their site structure is whether they should set up subdomains or subdirectories. Before getting into the weeds to discuss which one is better for SEO, let’s pause to clarify what makes them different.
What is a Subdomain?
Site owners might use a subdomain to separate a section of a website from the root domain. For example, Disney has created multiple subdomains that each serve a different purpose:
Google sees subdomains as entirely different websites. Any connection between them is dependent on the interlinking system a site owner puts in place.
What is a Subdirectory?
A subdirectory lives under the main domain and holds topically-related content — much in the same way folders organize categories of paperwork in a filing cabinet. For example, the Victorious website is a system of subdirectories.
The Debate About Subdomain vs. Subdirectory SEO
There’s a lot of debate about which site structure is better for SEO, and I have my experience-based opinions. (I’ll get into those in a minute.)
But, first, what does Google say about using subdomains vs. subdirectories?
What Google Says About Subdirectory vs. Subdomain SEO
According to John Mueller, a Senior Webmaster Trends Analyst at Google…
“Google Web Search is fine with using either subdomains or subdirectories…use what works best for your setup and think about your longer-term plans when picking one or the other.”
According to Mueller, the question of subdomain vs. subfolder is irrelevant for Google’s search algorithms. His point is that search bots process them the same way. (Watch the two-minute video for John’s complete thoughts about the SEO impact of choosing subdirectories or subdomains.)
This statement stirred up a lot of controversy in SEO circles because some case studies appeared to contradict Google’s assertion that it treats subdomains and subdirectories the same.
Rigorous Inquiry or Sensationalist Clickbait?
It’s much easier to whip up a frenzy of conspiracy theories about Google deliberately misleading SEOs than it is to dive into the nuances these case studies uncover. I’m not going to pull any punches here; without a detailed discussion about what makes these particular cases true, the blanket statements they propagate have no purpose beyond boosting the notoriety of those who sow doubt and confusion about SEO.
Getting Closer to the Truth About Subdomains & SEO
Let’s clear away the smoke, put away the mirrors, and talk about context, implementation, and resources.
1 – Why Context Matters for Subdomains
Exactly which content a site owner splits off into a subdomain will significantly impact indexing and ranking. For instance, pulling blog content directly related to your primary business into a subdomain is a different matter than separating a segment of your content that stands apart from your primary business. Let’s reconsider the Disney example above.
Here, Disney is targeting specific audiences with subdomains, which is very different from a business choosing to relocate only their blog content like so:
Moving blog content onto a subdomain (like in the case studies cited in the tweet above) would have an entirely different impact on search rankings and organic traffic.
2 – Implementation Matters
There are as many different ways to implement subdomains and subdirectories as devs who do the work. As I’ll explain below, regardless of the site structure you choose, strategizing for domain authority and link equity, avoiding keyword cannibalization, and using sound technical practices will all figure into your SEO results.
3 – Resources Are Everything
In summary, Google will index a subdomain or subdirectory the same way, but whether or not the average business can achieve SEO success by using subdomains depends on what content goes where, how it implements the structure, and the available budget for SEO strategy and maintenance.
Businesses that experience great SEO results with subdomains are the exception to the rule, and their success is often despite their chosen site structure, not because of it.
Take our Disney example — Disney has nearly unlimited resources to dedicate to SEO activities that will boost visibility for their portfolio of subdomains. Likewise, they have no shortage of tech budget to maintain and scale those domains. In the grand scheme of businesses vying for ranking position, Disney’s outsized resources make it uniquely able to make subdomains work for them.
Recommendation — Subdirectory SEO for the Win
Victorious recommends our customers structure their sites with subdirectories for the best SEO results.
Why Subdirectories are Better for SEO
Link equity is a search engine ranking factor based on the concept that links can pass value and authority from one page to another. Whether a link passes equity is determined by the referring site’s quality and its thematic relevance to the content on the page it’s linking to. Links to your site from authoritative domains signal your content quality to Google and boost your site’s authority within your topic or industry.
Domain authority scores are metrics developed by third-party companies Moz and SEMRush, to quantify the authority of websites. It’s important to note that these are trailing metrics, not ranking factors. As a trailing metric, domain authority can only gauge a site’s potential to rank higher than its competitors in search engine results.
When I talk about domain authority, I’m referring to site authority in a general sense, rather than pointing to either one of these metrics — which have limited use to predict the likelihood that one domain will outrank another.
How a Subdirectory Structure Relates to Link Equity & Domain Authority
Using subdirectories concentrates your keywords and link equity onto a single domain. When you keep these ranking factors focused on your root domain, you’re accumulating signals that Google will interpret as more helpful to searchers (domain authority) and translate into better search rankings. Conversely, spreading keywords and link equity across multiple domains will dilute your authority and require you to pour more effort and resources to get subdomains to rank competitively.
Subdirectory SEO – A Bonus
Another reason I recommend subdomains for better SEO is the benefit of having accurate sitelinks in your search listings.
When searchers Google “Victorious SEO,” they’re going to find this:
The six sections listed under our homepage are called sitelinks. Google puts important links right in the search results to help users jump directly to the page on your website that they’re interested in — directing users to the best results in the shortest time.
The appearance of sitelinks also makes your listing more prominent (and credible) in search results, a bonus for branding and click-thru rates.
How to “Get” Sitelinks
There’s no magic button to add sitelinks to your search results. A clear structure that signals how pages on your site relate to each other and makes it easier for Google to crawl your site will increase the likelihood that they’ll pull the right sitelinks into your search listing.
We only show sitelinks for results when we think they’ll be useful to the user. If the structure of your site doesn’t allow our algorithms to find good sitelinks, or we don’t think that the sitelinks for your site are relevant for the user’s query, we won’t show them.
You can’t control sitelinks. Google’s algorithms automatically pick them up. Suppose you link to some of your subdomains, and Google determines they have more weight and relevancy than some of the core content on your root domain. In that case, those subdomains might appear in your sitelinks — causing confusion for searchers and potentially prompting them to question the credibility of your site. That scenario would put your core pages (and, by extension, your root domain) in direct competition with your subdomains for traffic — not a situation you want to find yourself in.
Unless you have a compelling business reason to create subdomains for your content, your SEO strategy will be better served with subdirectories. Having one root domain gathers your link authority in one place, concentrates cumulative keyword gains, communicates a clear structure to Google, and keeps your overhead low. Subdirectories are easier for you, easier for Google, and easier for your visitors. Win. Win. Win.
Want to Know More About Site Structure & SEO?
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