(Revised 23 Feb 2016)
The SEO technique for optimizing any website, called a “Silo” is pretty well described on the Bruce Clay site. But actually implementing silos on a big website can be an exercise in frustration unless you know what you’re doing.
To optimize (SEO) a large site with a lot of categories and huge link menus, it becomes really important to do the siloing right.
If every page of a large site links to every other page of the site through the menu system, then any PageRank coming to the site from Google is shunted around and diluted, not concentrated into your main categories and not USED the way it should be to get you better rankings at Google.
The standard method of making a big menu that shows up at the top (or left side) of every page is NOT conducive to good search engine rankings, for a large website. Especially if they are HTML/CSS drop-down menus using A HREF tags as links. (As pretty and clever as those menu systems may be).
Here’s the theory on which this is based. (I have seen no proof of this, other than the increased PageRank of sub-pages of a site after setting up a silo system):
What happens when you have a big menu on your home page with, say, 100 links to pages in your site, is that the PageRank coming to your site from Google is cut up into 100 pieces and distributed to all 100 links. Google says they give more weight to text links than menu links, and I’m fairly sure that’s true.
What happens if you link TWICE to certain pages (from a top menu and a bottom menu, say)? Well, then you’re just wasting precious PageRank — Google only counts the first link for PageRank purposes. It still divides by 100 (if that’s the number of links from your home page) but it only passes PageRank once — a little bit gets “leaked” or wasted, then, for every double-link you have on your home page.
But, you say, “Those big navigation menus are important pieces of my human interface for my site. I don’t want to get rid of them entirely.”
So, how can you focus the PageRank down to your “silos” and still have those awful, huge menu systems? I’ll tell you in a minute….
We’ve achieved very good rankings for several websites, and increased the PageRank of their main sub-pages, by putting the main pages they want to rank for at Google, as the only VISIBLE (to Google) links from the home page. That’s just one step of the silo process, which I’ll outline in full below.
There are problems with this, of course:
- “How do you still have a user-friendly navigation system that shows the rest of your website to human visitors?”
- “What about linking to our contact page on every page?”
- “What about the links to our ‘Specials’ page we have on every page of our site?”
- “What about the link to the blog that we’re supposed to have on every page of our site?”
Those questions are answered below.
The Silo Process for Large Websites:
1. Keyword Research.
Sorry if you thought it might be something else. Doesn’t everything start with keywords?
Figure out the main keyword phrases for which your site should rank well at Google. Pare that down to about a dozen terms. If you aim for more than a dozen keyword phrases, then the silo process will be less effective. For the purpose of the silo process, make sure you:
- a) aim for keywords that are relevant to what the site is actually about, and
- b) aim for keyword phrases having a good volume of searches at Google every month.
We use the Google AdWords keyword planner to thoroughly research that information, but WordTracker and other keyword research tools are also very valid and work well. Use the keyword research tools you’re comfortable using.
What I’m saying here is, don’t use the silo process for “long tail” keywords. If you try to have a thousand silos in your site, you’ll fail. Try for a dozen — that’s an attainable goal!
Example: For a large drug rehab website, the main, targeted keywords, based on our keyword research, might be:
- drug treatment
- drug addiction
- drug rehab
- marijuana addiction
- heroin addiction
- meth addiction
- oxycontin addiction
- cocaine addiction
- crack addiction
- drug rehab clinic
2. Set Up Folders on the Server for Those Keywords
Make sure you have your folders organized by content, focused on those keywords.
These are going to be your “silos”.
So in my continuing example, your folders (directories on your server within the www/ or http_docs/ or public_html/ folder) would be:
The way I’ve set up the folders above, each of these folders (directories) is going to be a silo.
3. The ONLY Links from the Home Page Go to These Folders
From the home page of the site, use standard <A HREF > links ONLY to these folders. One reason for doing this is that some of these links will become the site-links under your site’s listing at Google, if you can get your site to the #1 spot at Google, instead of terms that typically show up under Google site-links, such as “contact” and “about us”. Think for a moment about why a contact page or an about page might show up as a sitelink… Here’s my conclusion — Google makes them sitelinks because webmasters typically link to them from every page of a website. They must be important, right? So don’t do that unless you really want your contact page or about us page as sitelinks.
So you CAN have a lot of other links on the home page — just don’t make them Google-friendly links. You can even use standard A HREF links. Simply put those in an iframe and then exclude Google from crawling the iframed file. (Use your robots.txt file to do that) the file called by the iframe (your menu for humans) is then never crawled by Google. Viola! Links within it won’t count, for PageRank purposes. I have extensive anecdotal evidence that this works very well, because I’ve done it with sites and they routinely rank highly for very competitive keywords. Of course, your mileage may vary.
4. From the Folders, Only Link UP or DOWN
From the main silo pages, such as (in my example):
drug-treatment/index.php (or asp or html – it truly doesn’t matter what the file extension is)
you use A HREF menus that link only DOWN into that folder, and UP to the home page. DO NOT LINK ACROSS to the other main categories/silos/folders of the site.
drug-treatment/index.php might then use A HREF links to link:
- up to the home page
- down to drug-treatment/dual-diagnosis.html
- down to drug-treatment/outpatient.html
- down to drug-treatment/inpatient.html
- down to drug-treatment/admission/index.html (which might have more pages in this folder)
These sub-pages can link across to other pages within the same silo, but not out of the silo to other categories or folders.
Again, you can have as many links to the other categories and pages within those categories as you think you should have, within menus for humans to use to navigate the site, but those links MUST be in a non-Google-friendly menu. In other words, in an iframe.
All the content of the site is then put within those folders, or other folders such as
At some point you’ll have to put each and every page of the existing website (500 pages? 50,000?) onto a spreadsheet and figure out which silo/folder and sub-folder it should be in. This process is called “taxonomy”. Taxonomy is your friend, at Google. And, of course, you’ll need to set up 301 permanent redirects to the new page location from the old page location.
5. Go Deep!
You can have silos that keep on going down, deep into the pages within a website. Using my hypothetical drug rehab site as an example, you could do a sub-silo for drug-treatment/heroin/, containing pages such as:
and so on. You could have 20 or 200 pages about the rehabilitation and treatment of heroin users, each with its own unique content but all of them focused on the rehabilitation of heroin users.
In this example, the methadone page (methadone is a heroin substitute) would link upward to the drug-treatment/heroin/ folder it is in, but NOT across to every other page of the silo it is in, using A HREF links.
So what Google then “sees” when it crawls your site’s link structure, is:
- home page – linking to 10 folders.
- each folder linking down within itself and up to the home page.
- each sub-folder linking down within itself and up to its main page within that folder.
To a web crawler like Googlebot, this gives your site the appearance of being neatly organized into folders, making it simple to figure out your subject matter, and makes for an easy and certain categorization in their index under the keywords that YOU picked.
PageRank coming from Google, when the site is siloed properly, is then smoothly distributed through your home page to your main sub-pages, then down to their sub-pages, and so on. It’s not dispersed across a hundred links, then another hundred links on every page. It’s the difference between a fire hose of page rank, and a sprinkler.
6. Take Advantage of Off-Site Links to Sub-Pages
If you have a page that has many links coming to it from off-site, then it can be its own silo, as well. It works like the home page: Google flows PageRank directly to that page, and you can flow that PageRank down to where YOU want it to go, if you organize the menus on that page, so that Google only sees the links you want. Your Google PageRank coming to that page directly from Google (not via the home page) will then flow from that page only to the pages you link to.
In our example, that page with many links to it from other websites, giving it its own PageRank, might be:
Turn that page into a silo by only linking UP and DOWN. Link up to
- drug-rehab-clinics/ (the folder it is in)
link down to
You might need to MAKE a folder to do that.
That’s the silo method we use for our clients with large websites, and it works well.
We’d be happy to talk with you about “siloing” your website so Google can figure out what it is about, and help you attain better search rankings as a result. Feel free to call us at 541-655-0285 or contact us by email.