When a website goes into development most of the attention is usually paid to the design elements. That's obviously the most important thing, right? The images, the layout, the colors, the navigation, how the user will interact with the site? These are all important elements to consider and necessary for developing a site that provides the best usability experience for your visitors. But what often doesn't get enough attention is the site's directory structure.

When I talk of a site's directory structure I refer to both the file directory and internal link structures. They are two very different things, but in reality they should often mirror each other very closely, but not always perfectly.

Three directory structure types

There are two commonly, yet improperly, implemented directory structures. The first is the flat directory structure.

Page URL example:
http://www.site.com/page.html

Many might argue that this is the ideal directory structure but I disagree. Granted, if you have a very small site then a perfectly flat structure like this is the way to go. But once you're dealing with a site that has more than a dozen or so pages, it's time for a little organization.

A flat structure like this gives equal weight to all your site pages in a navigational context. The search engines don't see any hierarchy of importance, nor do the visitors get a sense of any kind of page categorization (though this can be implemented visually on the site). The problem is that once your site starts to grow a bit each page really isn't as important as every other and you need a file structure that accounts for that.

This is where your file directory structure best mimics your visual structure if you've implemented visual separations in your site categories. But before I get to that in more detail, let's look at the other improperly implemented directory structure. Instead of being too flat, this one has too many folders and sub-folders, and creates a more vertical directory structure than is necessary.

Page URL example:
http://www.site.com/dir1/dir2/dir3/dir4/dir5/dir6/page.html

I'm all for staying organized but this is a bit too ADD, even for me. The problem here is that the pages on the lowest level are so far away from the the home page that you're burying them, making them near impossible for the user and even the search engine to find.

That's not to say the search engines won't find them all eventually, but you're not making it easy being so many clicks away from the home page. There are some instances where this can't be helped, especially for very deep sites, but most e-commerce site's don't need to have products more than four clicks away from the home page.

If you already have your directory structure set up this way it may not be a good idea to go and change it. Instead, rework your navigation so that while the physical file structure may appear to be pretty deep, the internal link structure flattens it out a bit, much more like my ideal directory structure below.

Page URL examples:
http://www.site.com/dir/page.html
http://www.site.com/dir1/dir2/page.html

In this example every page is two clicks away from the home page. This is a simplification, and not feasible in all circumstances but feasible enough for many websites. Implementing a relatively flat directory structure such as this ensures that good pages are not buried and are easy enough for the user to find starting from the home page.

By setting up your directory structure this way you're also communicating the value of each of these pages. Buy not burying them under piles of directories and visitor click, the search engines understand that these pages are to be weighted as being more important than the others.

Proper Implementation

Before we leave this topic, I want provide just a little bit more information on how to properly implement your directories and sub-directories. By creating directories to group similarly themed pages (i.e. backpacks go in one folder, wheeled bags in another) you have the opportunity to add additional keywords into your URLs. You also have the opportunity to junk up your URLs by going overboard, creating a spammy looking site, so be careful not to do that!

Here is a good implementation of the ideal directory structure above:

Page URL examples:
http://www.site.com/keyword1/page.html
http://www.site.com/keyword1/keyword2/page.html

Here is a real life example of using keywords in the directory names in a way that makes good sense:

http://www.site.com/batteries/motorcycle/sYTX9-BS.html
http://www.site.com/battery-chargers/8-volt/BM12108E.html

You can see by this implementation that we're not "stuffing" keywords into these directories, but using them in a way that makes sense both to the search engines and the visitors. But before you get all directory happy, here is an example of what you don't want to do:

Page URL examples:
http://www.site.com/keyword1/page1.html
http://www.site.com/keyword2/page2.html
http://www.site.com/keyword2/keyword3/page3.html

I've seen sites that create a directory for every single page on the site. Don't do that. Directory folders should contain a number of pages that all pertain to a particular topic of the site. If you have pages that don't pertain to any particular topic then put those pages in the root folder, keeping in mind that not every page needs to be in directory folder.

Implementing a sound directory structure will help, not only with basic organization but with establishing the site's overall hierarchy. A good hierarchal structure can play a significant role in how well your site gets spidered and pages re-indexed in the search engines.