With all the talk out there about linking, one might be under the impression that the only links that count are those from other websites. While these links certainly play an important role these are certainly not the only important links.
When you're about to launch into your link work, why not stop and consider the ones that are easiest to attain and maximize first. That would be, the ones right there on your own site and those which you have total and complete control of. Properly used, internal links are like highways between your content where the search engine spiders stop and go.
The internal linking structure can:
Simply changing your internal navigation will not launch your site to the top of the rankings however it's important to use each and every advantage available to create a solid top ten ranking for your site that will hold it's position.
Internal links will get your pages doing better, they will help get your entire site spidered, they will help increase the value of internal pages and they will build the relevancy of internal pages to specific keyword phrases.
We have seen websites that, once the search engines find all of their pages, you find that they are ranking on the first page and seeing traffic from phrases they never thought to even research or target.
This may not necessarily be the case for you however. Having a larger site with more pages related to your content will boost the value of your site overall. You are offering this content to your visitors, so why hide it from the search engines ?
Pages can be hidden from search engines if the linking is done in a way that they cannot read. This is the case in many navigation scripts. If your site uses a script-based navigation system then you will want to consider the implementation of one of the internal linking structures.
Additionally, image-based navigation is spiderable however the search engines can't see what an image is and thus, cannot assign any relevancy from an image to the page it links to other than assigning it a place in your website hierarchy.
While we will be discussing PageRank (a Google-based term) here; the same rules generally apply for the other engines. The closer a page is in clicks from your homepage, the higher the value (or PageRank) the page is assigned. Basically, if you have a page linked to from your homepage it will be given more weight that a page that is four or five levels deep in your site.
This does not mean that you should link to all of your pages from your homepage. Not only does this diffuse the weight of each individual link but it will look incredibly unattractive if your site is significantly large.
Figure out what your main phrases are and which pages will be used to rank for them and be sure to include text links to these internal pages on your homepage. It is important to pick solid pages to target keyword phrases on, as you don't want human visitors going to your "terms and conditions" page before they've even seen the products.
If that hosting company noted above has a PageRank 6 homepage, the pages linked from its homepage will generally be a PageRank 5 (sometimes 4, sometimes 6 depending on the weight of the 6 for the homepage). Regardless, it will be significantly higher than if that page was linked to from a PageRank 3 internal page.