After looking at some seo companies, I notice that their index page focuses on the keyword "SEO", and other pages of their website also have SEO in them, but they don't link back to their main index page with the anchor text "SEO".
I'm sure this means they have a keyword cannibalisation problem, or are the search engines smarter than I think? Can the search engines work this out without the user needing to link back to every single page with the keyword to try and avoid this problem?