Initially, the World Wide Web was comprised predominantly of static web sites. Each URL within a web site pointed to an actual physical file located on server’s file system. Therefore, a search engine spider had a very little to worry about. The spider would crawl throughout the web site and index every URL in a relatively straightforward manner. Problems such as duplicate content and spider traps did not typically exist.
Today, dynamic web sites dominate the World Wide Web landscape. Unfortunately, they frequently present problems when one looks at their URLs from a search engine’s perspective-especially with regard to spidering.
For example, many dynamic web sites employ query string parameters that generate different URLs that host very similar or identical content. This is interpreted as duplicate content by search engines and this can get the pages penalized. The use of many URL parameters may also result in spider traps, or in linking structures that are hard to follow by a search engines.
Now I’m gonna discuss both the topics in dept, do read this, as this could be the thing which would result in better performance of your site.
Static URLs
Static URLs do not include a query string. By this definition, a URL referencing a PHP script without parameters is still static.
example:
http://www.yourdomain.com/contact-us.html
http://www.yourdomain.com/site-map.php
Static URLs- even those generated by a PHP script- typically pose no challenges for a search engine.
Dynamic URLs
Dynamic URLs are those that include a query string, set off by ?, a question mark. This string is used to pass various parameters to a PHP script. Multiple parameters are delimited by & and then appended to the query string. A typical dynamic URL looks like the following:
http://yourdomain.com/product.php?category_id=&product_id=2
In this example, product.php is the name of a physical file containing a PHP script on a web server. The highlighted section is the query string. When a web browser makes a request to the PHP script with a particular query string, the script may then present differing content based on the various parameters.
” Because the query string value affect the script’s output, a search engine typically considers the same file name with differing query strings as completely different webpages, despite the fact that those pages originate from the same physical script file.”
However, the script does not necessarily have to present different content based on different permutations of the query string-which is the basis of the most common cause of duplicate content. The most trivial example of this is when you add a parameter that does not change the presented content at all, such as in these examples:
http://www.yourdomain.com/product.php?product_id=2&extra_param=123
http://www.example.com/product.php?product_id=2&another_extra_param=456
Session IDs and various other tracking IDs are two very common culprits. In the worst case, a search engine may not index such URLs at all. Therefore, the use of such parameters should be avoided as much as possible.
Dynamic URLs- especially those with more than two parameters- may pose problems for search engines, due to the increased difficulty in ascertaining how to spider the site. Matt Cutts of Google affirms all of this on his blog at http://www.mattcutts.com/blog/seo-answers-on-google-video/. Lastly, a dynamic URL may look less appealing or relevant than a well-constructed static URL to a human user.
In some cases, search engines may attempt to eliminate an extra parameter, such as a session-related parameter, and index site URLs without it. Depending on this functionality is neither realistic nor wise, however.
Fortunately, there are many ways to improve URLs with regard to indexability as well as aesthetics. This typically involves eliminating any unnecessary parameters, and/or obscuring the dynamic parameters using keyword-rich static URLs.
