How your format your content and how you setup your website and its structure, is not something that should be taken lightly. Navigational structure is very important, both for you users as well as for search engines. Did you know, that the more clicks it requires to reach a certain webpage, tells a lot about how important the webpage is? The more clicks it requires to reach the webpage, the less important it must be.
The logic is simple, as a webmaster, you’ll want to show your users the most important webpages first. The more the content is buried, the harder it is for both users and search engines to reach that page. The harder it is to reach, the less important it must be.
Search engines has taken this logic and implemented it in their algorithms. Search engines tries to understand the importance of each webpage on a website, a way to do this is to look at the amount of required mouse clicks on links, from the frontpage of the website, to the page in question.