When to use subdomains: 3 reasons for them (& a few against)

A computer desktop has starting point, a series of folders and subfolders, and ultimately a desired location or file. A website has the same qualities. One distinction is that while a desktop is designed for productivity and personal enjoyment, most websites are designed for profitability and other people’s enjoyment.

Those external factors, coupled with how quickly website best practices evolve, mean that something as benign as website navigation architecture can have a ripple effect.

Today, most SEO, UX and other digital marketing experts might recommend websites avoid subdomains where possible. www.website.com/subfolder should be used instead of subdomain.website.com to align with current best practices and avoid potential negative side-effects. It’s not always that easy.

Here are three scenarios when subdomains might still make sense, plus one that you should avoid.

Mobile (Adaptive) Friendliness

mobile smartphone b2b marketing content seoA subdomain approach can be a way of providing a mobile-friendly experience to visitors.  As we move away from a desktop-centric internet to one that favors the mobile experience, brands are trying to determine the best way to present a mobile-friendly alternative for their rapidly changing audience. Responsive design versus adaptive design is a debate that endures.

Responsive Design

Responsive design means a website design should work regardless of the screen it’s on. Such websites are designed to scale with the screen being used, with elements like images, columns, and navigation shifting in tandem with the screen pixel count. If you open a responsive site on your desktop browser and slowly reduce the window size, you may be able to render the layout to that of a mobile or tablet screen in real time. (Try it with Brafton.com! It’ll work.)

Adaptive Design

Adaptive design supports a unique experience for each device type. Such websites will determine the device used and then render the appropriate layout. When this happens, a mobile or tablet user will find the URL reload as m.website.com or something similar. This type of approach warrants a subdomain.

For any number of reasons, a brand or individual may prefer to pursue a website with adaptive design. From website redesign deadlines and efficiency, to analytics strategy, to giving users the option of specifically requesting a desktop or mobile experience, to raw design preference, not every brand is leveraging responsive design at this time. Most authorities will recommend responsive design, but the most importantfactor is providing a mobile-friendly experience.

Adaptive layout is generally hosted on a unique subdomain. A desktop user might go to www.website.com, while the mobile user receives m.website.com, and the tablet user is treated to t.website.com.

Limited-Use Content Management System or Marketing Automation Integration

tuning up your marketin engineMany websites are purpose-built, and a subdomain can logistically be the best way to add something extra.  A retail company with brick and mortar stores will often have an eCommerce website so users can skip the trip to the store and purchase in the comfort of their home. Banks have websites with a strong privacy components, requiring registration and login, so users can become new customers and manage accounts online.  Tools like a content marketing system (CMS) or marketing automation platform (MAP) are an afterthought.

These tools are invaluable because they help marketers, web administrators and developers manage their websites much like an operating system helps users manage their computers or phones. Some brands that have a custom-built website but recognize the value of a CMS or MAP for digital marketing purposes will install one on a website subdomain for those specific marketing purposes.

Corporate Blog

A common scenario for a CMS on a subdomain is for a corporate blog. They are often natural fits for blogging, and it can be easier for a brand with an established online presence to create a purpose-built blog on a subdomain (blog.website.com) than to install it on a subfolder (www.website.com/blog). Though it is not ideal, it is an option, and is certainly better than not having a corporate blog at all.

PPC Landing Pages

One of the values of a MAP is the ability to quickly and easily create conversion-focused landing pages for PPC, email, or any promotional channel. Landing pages created in this way are typically associated with a subdomain. For instance, a user might normally engage with a brand at www.website.com, but after clicking on a paid search ad, they would be directed to promotion.website.com/landing_page.html.


map local seo location addressPlenty of brands operate in multilingual countries. But, these are global times. When brands expand into new regions, that often means expanding into a new language and so each page is usually recreated in each language. From a website architecture standpoint, there are different ways to provide a browsing experience in the desired tongue or country of the reader.  The decision ultimately comes down to using a different domains, different subfolders, or different subdomains to do this.

Domain Approach

The most common way to accomplish this is offering different language or country options at the domain level. An American user may go to www.website.com, but a Canadian user may prefer www.website.ca, and a Japanese user www.website.jp. This is the most intuitive option for users and search engines, but there’s no guarantee the domain is available in each country.

Subfolder Approach

Brands with a multilingual or an international presence may choose to take advantage of distinct subfolders to accomplish a unique experience for each country or language, or combination thereof. An American user may go to www.website.com/en, but a French user may prefer www.website.com/fr, and a Japanese user www.website.com/jp. This is a solid option because it only requires the root domain.

Subdomain-Level Approach

Another option is changing the language/country at the subdomain level. An American user may go to en.website.com, but a French user may prefer fr.website.com, and a Japanese user jp.website.com. This approach is approximately on par with the subfolder approach. Both this approach and the subfolder approach have the challenge of being less intuitive than the domain-level approach. Is fr.website.com for French speakers, or French citizens? The subdomain approach is also unfavorable to SEO.

Avoid Thematic Subdomains

There was a time when it was arguably a best practice to divide major website sections into subdomains by theme. An automobile website might have cars.website.com, trucks.website.com, and vans.website.com. The perceived SEO benefit was that a search query like “trucks and vans” might yield both the cars.website.com and trucks.website.com subdomains. At that time, search engines treated subdomains more like distinct domains. That was 2010, and times have changed. Here’s how:

  • Subdomains may result in organic search cannibalization. A similar strategy today is likely to result in cannibalization. Search algorithms have changed so websites are interpreted more holistically, and it’s less likely that a search query will yield multiple listings from the same site. It is also more difficult for internal link authority to transfer across subdomains compared to the same domain.
  • Subdomains may send visitors to the wrong experience. From a sales perspective, if a subdomain with little relevance appears in search engine results in place of a directly relevant page that’s optimized for conversion, it can be difficult to overcome and might damage the bottom line.
  • Common content marketing mistake: corporate blog subdomains. This is also true of corporate blogs on subdomains; if a popular article about a core search term is a brand’s top listing for that term, those people will hypothetically read the article instead of reaching the desired landing page. Instead of visitors being treated to a well-designed interactive car buying guide page on the hypothetical automobile website, they might be shown the “5 hilarious car buying guide fails” article from 2013.

Best practices currently recommend that website themes be divided by subfolder. For the hypothetical automobile website, the ideal mix would be www.website.com/cars, www.website.com/trucks, and www.website.com/vans.

Balance Effectiveness with User Experience

At the end of the day, our recommendation is that it’s currently better to leverage a subfolder-centric navigation strategy over a subdomain-centric navigation strategy because they:

  • Align better with SEO
  • Provide a better user experience on average
  • Integrate with future digital marketing innovations

With that said, many successful brands, individuals, or groups have tenured web presences that are effective despite using subdomains. Those same entities tend to delay changing their website architectures until a major website overhaul happens.  They risk accruing SEO penalties in the meantime.

Approaching website strategy with agility, adherence to best practices and goals in mind will allow you to make an informed decision about your long-term approach.

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