Search Engine Friendly URLs or SEF URLs, are urls that make sense to both humans and search engines. Nowdays all modern sites should use SEF URLs for search engine optimization. This is a good way to improve your rankings among search engines and bring more traffic to your website.
non SEF URL - http://www.example.com/index.php?type=article&id=1544&mod_conf=1
SEF URL - http://www.example.com/this-is-a-fantastic-article
The first url of this example is non SEF. That means that seach engines cannot extract any information from this. The only thing this url includes, it's data (GET variables) which is needed by this PHP application in order to display the appropriate content to the visitor. The second url which is SEF, has information that is usable by any search engine. In addition the url is more friendly for the visitors and they can easily assume the expected content.
But how it works?
Actually the implementation of this technology is not rocket science. It can be implemented by developing a rewrite engine or using, if we have developed our website with a CMS or a Framework, the embedded engine. This engine is also called a router. Every content management system (Joomla, Drupal etc.) has it's own rewrite engine but requires certain configuration in order to be optimized.
This rewrite engine actually "says" to the webserver that everything that follows the domain should me passed to our application as variable(s). Then our application identifies the content that it should be displayed to our visitor. The actual alpharithmetic text that follows the domain name is stored by the application in the database. Every cms names that text with it's own way. For example Joomla calls it alias while Magento calls it URL key.
How big SEF urls should I use?
Keep in mind that search engines and especially Google prefers sort urls. So if you have big titles on your content, keep for the url the most important part that you want to push up on search engine rankings. Search engines will crawl your content anyway, so SEF URLs it's an important step but search engine optimization require several techniques and technologies in order to be achieved.
Written by Michael Strigkos
MSc Com Engineer - Web Developer