Mesh linking is used when all pages are considered equally important (to theme, topic, and keywords). This is the simplest linking method in that each page on the site links to every other page on the site. Most sites use mesh linking by default without thinking about it by virtue of having the same menu or navigation bar on each page that contains the same links. This evenly distributes Google Page Rank among all pages in the site, which is generally not ideal. The following figure illustrates this concept.
Mesh linking – each page links to every other page
In the above example, note that each page links to the lesser important About Us page. So why funnel precious PR value to it? Use hierarchical linking whenever possible!