Navigation does more than shuttling customers around your site. In addition to its obvious usability and design functions, navigation can be optimized to improve organic search traffic. Well-optimized navigation strengthens the flow of link popularity throughout your site while sending relevant keyword signals, both of which are important to driving organic search traffic and sales.
Think of the aggregate power of every link that comes into every page as the lifeblood of a site. Search engine optimization professionals like to call that lifeblood “link juice.” To keep the site healthy and able to rank for the most keyword phrases possible, that lifeblood link juice has to be distributed throughout the site to feed every page. Internal links like navigation are the system of arteries and vessels that pass the link juice throughout the site.
Link juice doesn’t spread evenly across a site. Most of the link juice for most sites comes into the home page as the default place to link to. Think of the home page as the heart: a big pooling of vital link juice. The farther away you get from the home page, the less link juice is passed on. Each page along the step keeps a share for itself and passes on a lesser amount. The pages at the end of the line end up with the smallest fraction.
When a page has earned links from other external sites it becomes another pool of link juice. In some cases a resource or tool your site offers can become an even stronger pool of link juice than the home page. Well-optimized navigation ensures that those pools of link juice share their strength with the rest of the site.