How To: Internal Link Building for SEO
The easier you make things for the big search engines, the easier they’re going to make it on you so why not hand them a map?
A site map that includes links to all of your pages is a huge help to spiders and allows them to quickly see the entire structure of your site. Remember, the more indexing work you can get out of the spiders, the higher your ranking will be.
And it’s not just spiders who get some value out of a site map, your customer will be using it, too. There are plenty of Internet users who know exactly what they’re looking for and head straight to the site map to find it.