Why is a number included after each category name, product name or thread in URI?
It allows you to make well-structured URI for web crawlers as well as allows for the deletion of the last “directory” or “file” by the customer/visitor. Additionally, it allows the visitor to continue their browsing without reaching a HTTP 404/Not Found error page. For example, in the case of Magic SEO URL for ZenCart, when a customer deletes the last category in the following URI: http://www.magic-seo-url.com/demo/zencart/hardware-1/graphics-cards-4/ the new URI will be http://www.magic-seo-url.com/demo/zencart/hardware-1/ and everything works seamlessly. URIs with only one number looked better, but they lacked this great feature.