This is my take on an important Google Ranking Factor:
Google Ranking Factor: Links within the domain
Links within a site count toward a page’s link profile, so all navigation links and contextual links are positive votes for the sites pages. In theory, I believe a page’s link profile should be at least equal to the total number of pages within the website. This would be achieved by having all pages accessible within the navigation structure as part of the page template. By adding links in context, a page can also gain thematic strength through the link anchor text, the immediate context around the link anchor, and the wider page context, but to only a small degree. A rich navigation and contextual link count for a site might be around 5 to 50 times the number links as pages in the site, so a healthy site with 20 pages might expect to have around 100+ links pointing to every page.
Statistical model: Count
Dependencies: Links-to-context volume density may be a consideration
Measure: – for below norm, + for above norm, possible penalty for ++ based on density