SEO Strategies: Subdomains and Subdirectories

SEO strategies using subdomains and subdirectories: the hottest search engine topic of 2007? Maybe not. My readers, though, seem to have “subdomainia.”

Last week, more wrote to me with great SEO (define) questions. At the risk of hurting some feelings, I’ll answer only one more reader for now and help her with some SEO strategies using subdomains and subdirectories.

To be honest, I was a little burned out on the whole subdomain topic. Here’s what Maria wrote to me that got me going on SEO strategies and subdomains again:

I really liked this article. But what is going to happen now with subdomains with the new changes in Google? They will no longer serve as another result on the SERPs. A lot of companies will lose a result on the SERPs leaving space for other results that may hurt companies’ brand and products.

Maria asks an excellent question. Googler Matt Cutts recently addressed the topic of how Google handles subdomains. Here are some of my thoughts about Matt’s post.

When to Use SEO Subdomain Strategies

Subdomains should only be used when you have enough vertical content to support a standalone Web site. Subdomains are effective because they “piggy back” on the value of the root domain, whereas if you bought a new domain, it would have no authority/age. Plus, there are some unique things you can do from a SEO perspective.

I’ve built Web sites with subdomains with hundreds of pages of quality content. Those subdomains have a great deal of value in the search engines. Search engines value the root of the subdomain (example: as another home page for the Web site. For the most competitive keywords, the home page of a Web site is where I focus my SEO efforts.

If you have multiple verticals of your business competing for search engine ranking, you can build a subdomain/content strategy to help you gain traction for multiple sets of competitive keywords. Don’t create subdomains if you don’t have enough quality content to support a full-fledged Web site.

My friend Mike Black (a.k.a. “SEO Mike”) shared a concrete example — a mini B2B case study where he found subdomains worked well for a client’s niche product.

Our client sold industrial non-destructive testing equipment primarily for concrete and steel integrity. We set up a subdomain for a particular niche, aviation, to separate aviation equipment from all the construction-themed graphics on the site. Conversions rose significantly because the user now viewed the client as having greater experience in the subject matter. The site performed much better in the search engines with the products in the subdomain. Better conversion. Better search engine saturation.

How Google now treats subdomains hasn’t affected my clients’ Web site rankings. I believe this “change” targeted suspect subdomains and was designed to protect the integrity of the Google SERPs (define). For example, the subdomain for Wal-Mart ( is still in the same position this week as it was prior to this change, when I first cited it in “SEO for Brand Reputation Management.”

When to Use SEO Subdirectory Strategies

However, if you don’t have quality content — and loads of it — you’re better served by incorporating a subdirectory strategy.

Let’s say you run a business that targets multiple markets in the United States. So, you create “city name” pages that have virtually no unique content (a simple find/replace on city names). If you try the subdomain route here, the search engines will quickly catch onto your trick.

Remember, the search engines are trying to rank the best quality results for their users. If search engines determine you’re just trying to trick them with low quality content, they’ll do what’s best for the integrity of their SERPs. That means search engines won’t rank dubious subdomains.

Subdirectories (, on the other hand, can rank well with a unique first paragraph of content, header tag, and title tag/description/keywords tags. At least, that’s been my experience. Let me know what yours was and maybe — just maybe — I’ll write about subdirectories again next year.

Bottom line: try to think like the search engines. Don’t be an “algorithm chaser.” Try to always do the right thing and you’ll create a strategy that will last longer than the next algorithm (define) change.

As always, all the best to you and your SEO efforts!

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