WordPress permalinks are the permanent URLs to your individual blog post and blog page. This is very important part of your wordpress blog as it should be set first before you post any content to your blog. A change made later can really mess up your blog, which will create lots of 404 not found pages and will also bring down your blog search engine ranking. The URL of each blog post should be permanent and so its called permalink.

Setting a permalink should be your first step after you install your wordpress blog. Learn 5 things to do after you Install your wordPress blog. Default url structure is not recommended you should change to something, which is more sensible, and search engine friendly too.

You should never enter your blog URL in permalinks slot instead use the structure tags or combination of tags only. Always end your structure with either %post_id% or %postname% (e.g. /%year%/%monthnum%/%day%/%postname%/) so that each permalink points to an individual post. Because of performance reason, you should never start your blog permalink structure with the category, tag, author, or postname fields. Its best to start your permalink structure with a numeric field, such as the year or post ID.

Quick Tip: For more detail please visit http://codex.wordpress.org/Using_Permalinks