Having an optimal URL structure for your website straight from the beginning is very important, both because it will attract more readers and because it will be really difficult to change it afterwards.
An optimal URL structure will not use numbers or strange characters on the permalinks, it will be short and describe the content of the page.
Here is an example of a poor URL structure:
http://www.domain.com/2007/02/17/archives/p=?2176
Here is an example of an efficient URL structure:
http://www.domain.com/post-title/
An optimal URL structure will be more user friendly and it will also improve your search engine rankings. Most search engines, in fact, give a high weight for keywords present on the URL structure.
WordPress users can set an optimal URL structure by going into the Control Panel, then Options, then Permalinks. After you check the “Custom” structure and insert “/%postname%/” as a custom structure. This will make your permalinks display the post title right after the domain name.