URL Structure for SEO
What's in a name?
When the internet first appeared most pages where static HTML containing text and the occasional image. There was little dynamic content, which meant that it was easy to create pages with 'friendly' names (e.g. index.html) because every page had an explicit purpose and pre-determined content. This was search-engine and user-friendly, as both were given a clue to the content.
Databases and querystrings
But these pages quickly gave way to dynamic websites based on template pages that drew content from databases, and they used querystring-type URLs, e.g. product.asp?categoryID=1&productID=2. Typically these variables used integer variables because this was the logical choice for database administrators, and even when names where used (productID=MyProduct) there was still a question over the effectiveness of querystring parameters for SEO. All search engines provided guidelines that stated their crawlers were not as clever at crawling dynamic pages as they were static content.
Development of techniques to hide complexity and return to friendly URLs
As the ecommerce industry matured, the structure of the URL became an important consideration for two reasons. Firstly, however marginal, including keywords within the URL for what was otherwise an identical page might prove the deciding factor in reaching the top search engine positions. This was particularly important for online resellers who worked in very competitive markets. In this case, the search engines stated that dynamic content and querystrings were not the preferred option, so the aim was to trick the crawlers into thinking they were viewing static pages.
Secondly, there is the human factor. A friendly URL is a lot more appealing to click than a string of parameters that may or may not include a reference to what that person is looking for. The link also becomes a lot more memorable and transportable. If you want someone to remember a webpage, make the URL as short and relevant as possible. Therefore, querystring parameters gave way to cloaked/redirected pages that used artificial structures.
website.com/Product.asp?catID=1&productID=a now becomes website.com/digital_cameras/canon/ixus_80is, with or without the .html suffix. I'm sure you'll agree, the second link is a lot more understandable and appealing for someone who is looking for the Canon IXUS 80IS digital camera, and may be chosen in preference of the querystring link irrespective of their ranking in the search engine results.
Impact of the domain name and the mistake that most businesses make
One aspect of URLs that is often overlooked is the domain name. Accepting that all factors may ultimately have marginal effects on search engine rankings, the domain name plays a key role in establishing the right foundation.
Most businesses naturally register their business names as their domain names, and all subsequent search engine optimisation is applied to this domain name. This is a big mistake. SEO should be a consideration even before the domain name is chosen. By all means, register your business name as one of your domain names, if only to use for email addresses, but your website, particularly if it's an ecommerce site, should be as generic a reference to your product line as is available.
By using generic terms, whenever your website is mentioned, whether internally on your own pages, or externally, the link will include valuable keyword references. Search for any popular online product like digital cameras, notebooks or mobile phones and you'll find that many of the top results will include references to those keywords.
Branding generic domain names
Some traditional marketeers will probably shudder at the thought of using generic terms for domain names, and that's because they don't lend themselves too well to branding. If the name is easy to guess, it's also easy to forget, but keeping in the memory of the customer, and not allowing them to forget you, is another aspect of ecommerce entirely. Retaining the abundant customers that being #1 in the search engines will provide is a great problem to have.
Summary
In this article I've tried to address some of the key SEO factors of URLs. With the correct planning and due consideration, even these often overlooked attributes of your website will help your fight to the top of the results.
In the next article, I'll examine the difference between using folders and subdomains, and when it's advisable that each should be used.