From a SEO point of view, it is beneficial to have keywords as part of your url.  This is known as "search engine friendly" url or SEF for short.

There are my dynamic applications where pages URLs looks like ...

http://www.example.com/index.php?main_page=product_info&cPath=1&products_id=7

A search engine friendly url would look like the following instead...

http://www.example.com/dog-treats/bone-biscuits

Not only is this type of URL more search engine friendly, but I consider it more user-friendly as well.

Wordpress and Drupal has configuration settings that automatically sets up search engine friendly URLs for your post and pages.  Joomla has an sh404SEF extension that you can install.  Zencart has an Simple SEO URL mod.

Converting a application to Search Engine Friendly URLs often involves the use of Apache's mod_rewrite feature.

 After making your web application with search engine friendly urls, you will want to generate a XML sitemap of all those URLs and submitting them to search engines.