Regarding URL structure usability, for example, if a search engine discovers the URL http://www.webconsiderations.com, the search engine will be able to tell a lot about the site just from the top level domain name (a.k.a. TLD) even before the engine spider comes along to grab document content.
If a spider does grab document content and discovered a link to http://www.webconsiderations.com/website-design, the it will know there is more content and indeed a specific sub-directory dedicated to “website design”. URLs certainly aid and have significant value in effective ranking.
There are some common rules of usability that also apply to SEO best practices. A URL that is meaningful and properly structured for your website visitors will also apply to search engines. In addition, just as shorter URLs are normally preferred for your visitors (mainly because it is easier to remember and type), a shorter URL is generally preferred for a search engine.
When possible, the simplest URL should be used. For example, it would be better to link to http://yourdomain.com/products rather than http://yourdomain.com/products/index.html (or index.php). I would certainly recommend linking to the first.
With WordPress, you can easily accomplish this by logging into your WordPress admin panel and clicking Settings > Permalinks. Under common settings, select the “custom structure” option. Add /%postname%/ in the space provided and save your changes. This modified the URL structure of your WordPress website.
But what do you do if you don’t have a WordPress site and you want to apply the same type of URL structure to your standard website?
The simplest method is to create a sub folder with the name that you want to use as the URL. Copy the specific page for that document into the folder you just created and rename it index.html (or index.php if applicable) and upload it to your server. Then you would simply link to the folder and not the specific file. By default, web servers will serve a file named index.html or index.php without including the file name in the URL first unless you have linked to a specific file name.
There are certainly several other topics that could be discussed concerning URL structure and usability but by first simplifying your URLs, you are off to a great start in more effectively optimizing your website.