Silos Vs. Clusters [Website Architecture] Which One is Best?

“Just write great content” is a mantra that, while true, will only get you so far in the SEO game.

There's more than meets the eye when it comes to content and one of those things is how the content is arranged inside your website.

How you build your actual website is just as important as the quality of its contents.

Proper structure helps both crawl bots to navigate it more efficiently and optimize your crawl budget, and users to find more easily your relevant content and consume more of your great content.

So, in today's article, we're going to discuss Siloing Vs. Topic Clusters to try and discover which one is the best way to organize your content for your particular site.

1. Siloing: How it works

I'm going to throw here an image I'm sure ANY SEO who's ever googled “wordpress silos” has seen:

Now, find an orange Jellybean:

This 2012 article about WordPress Siloing by Stephen Cronin is one of the best guides there is to understand silos, old and all.

Do read it if you want to dive super deep into the subject.

But for those who just want the overview, here it is:

Where each silo is a main content topic within your chosen niche/industry.

You may also have heard of “parent-child” architectures. They're the same. Yellow boxes are parents, and green ones are children.

Because the most important reason of siloing is to keep pinneaples and bananas separate (so your topic relevance stays strong) you need to follow certain rules:

1.1 Silo Interlinking Rules

• Parent page should link to children
• Children will link to Parent 
• Children can link to siblings or Uncle(s) whenever appropriate
• Children shall not ever link to Cousins

Bruce Clay says that, if you MUST absolutely link a children to its cousin (because of UX) you should nofollow the link. 

Oh, and this includes your sidebar, main navigation, footer…

There's a fair bit of thought required for optimum UX on those elements WHILE keeping the silos perfectly clean.

1.2 Your URL Structure

Another part of siloing is how your structure your URLs or, better said, how you're organizing your content inside folders.

This is your typical siloed URL structure:

site.com/parent/child (post)

I don't recommend going 3 levels or more deep into a silo because you will end up with an extremely complex setup.

Also, with very long URLs.

But if you need to because, say, your site is gigantic; it would look like this:

site.com/parent/sub-page/child (post)

1.3 How to set that up

One of the tricky parts of siloing a site is doing it right from a technical POV.

(It's somewhat easy if you're building a site from scratch, but incorporating silos to an existing site is a headache. So many 301s… )

For you to set up parents, you have two options.

You either use Category pages, or regular pages

With categories, you have the limitations in terms of customizing them, typical from category pages (No Thrive Architect, no Divi, etc). There are plugins that add fancy functions to them, but I haven't tested any.

I do it in a different way.

I create pages, then with a .php function, make the pages the “first folder” aka the substitute of the category page.

Here's what you need:

1. Create a category. Say it's “cheese”, its slug is /cheese
2. Create a page with the same slug as that category: /cheese
3. Set up Yoast to look like this
4. Install this plugin to add custom .php functions
5. Inside “My custom functions” plugin, paste this function seen here.

function wpa_alter_cat_links( $termlink, $term, $taxonomy ){
if( 'category' != $taxonomy ) return $termlink;
return str_replace( '/category', '', $termlink );
}
add_filter( 'term_link', 'wpa_alter_cat_links', 10, 3 );

Your pages will now substitute your categories and subcategories (for as long as there is a page for each category and subcategory with the same slug and organized in the same “parent-subpage/subcategory” way) and your posts will be added as children to those pages.

1.4 Sidenote for greedy affiliates

As I was typing the section above, I could already see you doing this:

bestwhateverproductshq.com/best–widget/7000xjr-widget-review/

Mostly because I've seen it a lot of times.

Just in case you were really looking to get “panda”rized, this is how you'd like that URL to look instead:

bestwhateverproductshq.com/widgets/7000xjr-review/

1.5 Pros and Cons of Silo Structures

Let's have a quick recap on siloing, its good and bad.

Where Silos are cool

• Cleanest, shortest URLs
• Best SEO setup
• Ideal for MASSIVE auth sites
• thumbs-upBest UX

Where silos suck

• Technical setup is complex
• Very strict internal linking rules
• Subsequently a lot harder to implement at scale (with assistants and SOPs)
• thumbs-downApplying to existing, big sites is a nightmare.
• thumbs-downRequires in-advance planning

2. Clustering: How it works

Clusters could be considered a simpler, lazier way to organize content inside a website with still a fair amount of effectiveness and a lot less planning in advance.

Here's how a clustered site would look like

Yeah I know what you're thinking:

“oh ok, one is vertical & the other looks like a splash”

Well yes, but that's just the visual representation 😛

Clusters organize content by levels too.

Disclaimer, this is something I developed for affiliate sites, I'm a bit unsure on how to extrapolate this to other types of sites.

In the image above, “best camping tents” would be the top level, “best car camping tent” (is that even a thing?) is a second level, and then any other keywords like “best car camping tent for winter” would be a third level. 

We will also have product reviews, informational articles, some comparisons, etc.

2.1 Cluster interlinking rules

As I've mentioned above, clusters are more flexible. Before telling you the rules I follow, first some terminology:

• Top Level: The keyword/product that defines the cluster “best dog food”
• Second Level: Just a bit more specific “best dry dog food”
• Third level: Even more specific “best dry dog food for old mastiffs“
• Node:  A comparison keyword, A vs B “dry food vs wet dog food”
• Reviews: A single product reviewed “Royal Canin Shiz Tzu review”
• Info: Informational articles “is a 1 month old puppy old enough for dry food?”

So with that said, these are my rules:

• Every single piece should link to the top level (as it's the most competitive keyword usually)
• Top Levels link to second levels and specific product reviews (the ones covered, if the individual review exists) only
• Second and third levels can link to each other whenever it makes sense. Also to its specific product reviews if they exist.
• Nodes will link to whichever top/second levels they compare. This could be cross-clusters no problemo.
• Project DiagramInformational articles link to the top level they belong to (#1) and in-between each other. They may link to other info pieces on different clusters whenever appropriate.
• Project DiagramReview articles will link to whichever second/third page where they've been featured, exclusively.

So, to put all of the above in a simpler way, a cluster is designed to power up the most competitive pages because everything revolves around them. 

That's why for instance, I only do KGR stuff for my informational articles.

I ensure no competition the further from the “core” I move from. “Core” being our Top Level product review page.

That way, I guarantee referral traffic funneled from the informational posts to the money posts and some easy link acquisition. (if you're the ONLY good resource there is for something people look for, you'll likely be linked to)

Same with product reviews. I always start with the easiest ones and link straight to the top level.

But the golden rule really is: Whenever it makes sense from an UX perspective to link to a page we've got on the site, we'll link to it.

And the “it make sense or not” gauge for me is:

If I'm reading this particular sentence, would I appreciate a link to know more about XYZ?

This is how we build our done-for-you affiliate websites, by the way. 

See that link above? Makes sense 😉

2.2 Your URL structure

When you use clusters, things become easier on this end.

This is how URLs look like:

yoursite.com/your-target-keyword

As easy as it gets.

​Yes, things can get a bit cumbersome if you have thousands of pages and it is not as tightly closed relevance-wise as a folder structure, but allows you to grow your site in modules without much planning. 

Modules as in, you do all the dog food content, then add say, bird feeders as your next content expansion if you're a “pet authority site” and you don't need to go back to your categories because your top level category was /food/ while it should have been /dog/ if you're going to do /bird/ right? Then /food/ is a sub-level… you get the drill.

Careful tho! There is a caveat you should be aware of. And it's about removing stop words.

This is something I explained in detail on the On-Page SEO module inside The Human Proof Method, but here's the mess-up we're trying to avoid by leaving the stop words in the slug:

2.3 Pros and Cons of clusters

Let's have a quick overview of where clusters win and lose.

Where clusters are cool

• Simplest setup
• Easiest for progressive, modular expansion (that's unplanned)
• Because there are no folders, you can get the whole keyword in the slug.
• thumbs-upPerfect for small, very narrow sites.
• thumbs-upInterlinking is more flexible

Where clusters suck

• Topical relevance can get dilluted if you're too generous with your linking.
• Really large sites can become very messy
• I honestly don't know how I'd “clusterize” an eCommerce site for instance.
• thumbs-downCan be harder to conceptualize.

As you see, for as much as I like clusters for their simplicity, it isn't all roses.

Although, it is perfectly possible to incorporate clusters on a larger site (as Duke and Kelvin talked about on episode 36 of our Podcast)

3. Final Words: Which one should you use?

So, after all this uber-long blabla about what both silos and clusters are and are not, which one should YOU use?

Here are my thoughts.

Silos

• Use if you can plan ahead at least 100 pieces of content and you can clearly organize them in a spreadsheet with categories etc. From there on, any new niches or expansions you want to do will already have the structure in place.
• Use them if you are ok with spending more time tweaking stuff in WP, creating all the pages, subpages, categories, siloed sidebars etc for an extra SEO boost.
• Use them if you feel comfortable with all other topics regarding internal linking, slugs, keywords etc. I would say it's a more advanced configuration. I, for instance, have been building sites for two years now making a full time income and I'm just building my very first 100% siloedhardcore purist style site now. 

Clusters

• Use them if you know you want to start with a niche but don't have a clear idea on how you'll expand the site later in the future
• Use them if the section 1 of this article gave you a headache.
• Use them if you are attacking a VERY narrow niche (as you will already be uber-relevant, silos won't be necessary at all imho). This is regardless of the size.
• Use them if you're going to create a micro-site (10, 15 pages) that you just want to rank and flip.
• Use them if you already have a large site perfoming decently and you dont' want to mess with hundreds of redirects b/c URL structure changes. 

Alright, I'm hoping that last section really helped you decide which type of website architecture you should implement in your website!

For questions, kudos, or angry comments, leave them down below!