Before we continue with this chapter, it is time to introduce the concept of Google PageRank (PR). PageRank will be discussed in more detail in “Chapter 9 - All About PageRank”, but is discussed here in order to understand why it matters how you link pages on your website together
PageRank is a numeric value that Google places on how important a page is on the Web. PageRank is determined by how many incoming links there are for a page. Incoming links are links that point to a page from another page. Links may be located on pages on the same website (internal links) or on pages on different websites(external links).
Google figures that when one page links to another page, it is in effect “casting a vote” for the other page. The more incoming links (votes) there are for a page, the more important the page is to Google, generally speaking
Note: Google PageRank is but a single factor used in the ranking algorithm. Many
have over-hyped PageRank and therefore introduced complexity that probably don't even exist.
The proper linking between pages of your website, if done right, will help retain the total PageRank of your site and will also distribute or channel your site’s overall PageRank value to your most important pages.
Internal links share or distribute PageRank among all pages of your site. Links on your site that point to other websites can decrease your site’s overall PageRank, while links from other sites can increase your site’s overall PageRank.
In general, the more internal links there are between pages of your site, the more evenly distributed the PageRank becomes in your site. Let’s see why this is important.