Don’t Nest Your Pages Too Deeply

When Google crawls your site, it typically starts at the home page and then follows each link on the page to all your other pages. Google finds your home page in turn from following a link on another website that points to your site.

Google seems to attach more importance to files that are closer to the root folder on your server - the folder on your Web server where the home page file is located.
Some web designers however may create multiple folders and subfolders on the server for ease in maintaining lots of files.

Google may not value pages located in subfolders as strongly as files located in the root folder. In general, Google doesn’t like to index pages that are more than about three folder levels deep. Ideally, all pages should live in the same folder as your home page or at most be one level deep.