Taking the keyword selection one step further, it can be useful to design the website in a themed pyramid method as suggested by an industry specialist Brett Tabke in his article “Search Engine Theme Pyramids”. According to his theory, which is widely accepted in the webmaster community, each site is given a certain theme by the search engine when the site is indexed (Tabke 2001).
“Theme engines determine sites' "themes" by indexing the entire site as a whole. As a page is added to a search engine, it goes back to its database, pulls out all pages from that domain and indexes the entire set of pages as one” (Tabke 2000).
Furthermore, Tabke suggests that the SEO value of the root page is nearly non-existent while the more specific pages deeper down the web site have high SEO value and rank high in the SERPs, thus bringing in more targeted traffic. Below is an illustration of search engine theme pyramids by Tabke.
Source: Search Engine World