SEO Silos vs. Topical Clusters

Two of the most popular ways of structuring your website these days are with SEO silos, which have been around for a while, and topical clusters, which have gained a lot of popularity recently.

So which one is better for your use case, and why? Could we potentially use them together? Let’s dive in.

What is an SEO Silo?

We’re going to start off with silos, and silos are a hierarchical organization of content where related pages are grouped together based on a specific theme.

This right here is the bare bone structure of a website that’s building a silo, without all the internal links (we’ll talk about that in just a second).

So the main thing is that we start off with a theme, and for that theme we’re then going to have a bunch of different topics that we can dive quite deep into with subtopics and sub-subtopics and so on and so forth. But this right here, so this area right here, would be one specific silo inside of this website.

Now let’s talk about why silos have worked…

Why do Silos work so well?

So why have silos worked so well over the years? Well, the first thing is that the structure makes it very easy for crawlers to find all the pages, and as a result it prevents orphan pages, which is something that can happen quite easily when your website starts getting a lot of pages.

Number two, we demonstrate topical authority by building a thematically connected silo. We only send internal links to pages based on relevance, so as a result we basically create this little area of pages that are very, very closely connected.

And number three, when you start getting backlinks, the authority from those backlinks will flow throughout the whole silo and throughout the whole site, regardless of where those backlinks come in.

So how do we go about…

How do we build an SEO Silo?

So before we get started with silos, we have to do some keyword research so we know what pages we need to build. Let’s take an example of a travel website. Let’s say I’m building visitspain.org. Let’s say the main keyword that I’m after for this website is “best places to visit in Spain.”

I’m after for this website is “best places to visit in Spain.”

Now what are some subtopics that we can have for that main keyword? The first step topics would be all the different cities that you could visit in Spain, so we can have Barcelona as a subtopic, Madrid, Valencia, and so on and so forth. And inside of those topics we’ll have a bunch of different subtopics, so different things that we could do in those areas – best restaurants, places to stay, attractions, and so on and so forth. And we could even continue this further, basically talking about the different types of categories for all those different places. So under restaurants for example, we’re gonna have different types of restaurants, different price points, and so on and so forth.

And so this is what the basic architecture could look like for this website. We have that homepage with that main keyword “best places to visit,” then we have the main topics at the city level, so “best things to do in Barcelona.” Then we have the subtopics based on specific city features, like restaurants, hotels, attractions, “best restaurants in Barcelona.” And then the sub-subtopics where we’re basically breaking down those subtopics a little bit further, like “best sushi restaurants in Barcelona” as an example.

So what would the internal linking look like for this specific silo? Now everyone has an opinion on the best way of building a silo and specific rules, but this is what I’ve seen work best on my end.

So we do see a lot of arrows kind of going all over it, but the important thing here is this tip right here – internal contextual link for all the different arrows. Now the important thing here is that we’re not taking into account links from nav bars, from sidebars, and from footers – these are links within the body of the page.

So what we see is that we have four internal links going from the homepage to all the different topic pages, right? So we see a parent and child relationship, and they’re each receiving a link but also sending back an internal link. And that’s the same thing down here at the city level, and again the same thing down here at the city features level.

Now why does this silo work so well? The first thing is that again, we’re only connecting pages that are very close in relevance. But number two, and probably most importantly, let’s say that we get a backlink over here to our restaurants page. So what’s going to happen to that authority, to that link juice? Where is it going to go? Based on the internal links, we’re going to see that it’s going to go down to the vegan pages, to the brunch pages, and to the sushi pages. But because we have a link pointing back to Barcelona, it’s also going to go back out to Barcelona. And as a result, in some way it’ll flow over to hotels, to attractions, and it can even flow back to the homepage and so on and so forth to the rest of the website.

So the topical relevance is high and the authority flowing throughout the whole silo is well connected and also works quite well. Now this works well in theory…

A more realistic Silo Structure

But how realistic is this? For starters, we have to realize that not all of these pages will have the same value to us, and as a result we shouldn’t have the exact same number of internal links pointing to each page. For example, let’s say that I really wanted to rank the “Best Hotels in Barcelona” page – if I was actually interested in ranking the site, that’s probably one of the pages that would make me the most amount of money from commissions. So as a result, I’m trying to push more links to that page to increase the amount of authority that flows to that page and also the topical relevance.

Here’s an example right here – in blue we have that target page that we like to rank. Now we have links coming from all over the silo to kind of push that page a little bit higher up in the search results. So this is most likely what a more realistic type of structure could look like – we have interlinks coming from all different sides of the silo.

Now what about linking to other sides of the silo? Well, if we wanted to follow strict silo rules, theoretically we can only link within our silo. So let’s talk about the different relationships here. As we talked about before, this is a parent and a child relationship, and that kind of follows throughout the whole way down.

Now we are allowed to link to our siblings – so up here this would be a sibling, this is also a sibling. We’d also be allowed to link to our uncles – so if Sushi’s parent is Restaurant, then Hotels would be the uncle. So this link right here is also allowed because we’re still maintaining that silo structure.

But we can’t link to our cousins – so if we link from Attractions in Barcelona to Restaurants in Sevilla for example, that would be the equivalent of a cousin, and now we’re breaking our silo and now we’re diluting the topical relevance of our silo.

Now do I agree with this rule and am I sticking to it 100% when I am trying to build big silos? I really try my best to keep things within the silo, but sometimes there are internal links that make contextual sense and as a result I’ll break the integrity and I’ll dilute the topical relevance of the silo. But again guys, it depends how strict you want to be with these specific structures.

So what about anchor text?

What about Anchor Texts?

Well, anchor text allows Google to understand the context of the relationship between two pages when we’re using an internal link between them. So as much as we’d like to add a bunch of exact anchor text with that keyword that you want to rank, try and mix it up – try and follow the 80/20 rule where 80% of my anchor texts are variations of that main keyword, and then around 20% of random text like “click here”, “learn more”, etc.

Now guys, unless we’re building an e-commerce site or we have a massive website planned where we already know the themes, the different topics and subtopics, this silo structure might not make sense for your site. Instead, let’s talk about what you could do.

The first thing I recommend is still following some type of pyramid structure – that top-down approach seems to work quite well, and we even have John Mueller saying that it helps them understand the context of individual pages within a website.

Now apart from that structure, I would also probably recommend setting up content hubs or topical clusters, and these are quite similar to silos in that we still interlink collections of related content. But there are less rules, so they’re still great for topical authority, for spreading link juice, and they also work quite well with smaller sites.

And the beauty of topical clusters is that there are no rules about internal linking between clusters. So here’s an example by Ahrefs. We have two content hubs or topical clusters, whatever you want to call them – we have fruits and we have vegetables. Now tomatoes happen to be a fruit, but a lot of people think they’re vegetables, so there’s definitely a contextual link there that would make sense to link both of these clusters together. If we were building a silo, that would dilute the topical relevance of the silo.

Can Clusters and Silo’s work together?

There’s no real right or wrong answer when it comes to website architecture. There are a lot of different structures that are successful. The important thing is just making sure that your website is easy to navigate for both search engines and users.

And I actually think silos and topical clusters can coexist, right? Depending on the sections of your website, I can imagine an e-commerce site having a very structured silo for their category, subcategory and product pages, but having some type of cluster set up in their blog section.

Now let me know what you guys think – what type of structure you’re building for your website, whether it’s a silo, whether it’s a topical cluster – leave it all in the comments and I’ll see you guys in the next one.