Great post by Aaron Wall: What Does ‘Write Naturally’ Mean for SEO?
If too many of your signals are focused on just one word or phrase and you lack the supporting vocabulary in your document you may get filtered out of the search results for your primary keyword targets. It has happened to me several times, and it is a pretty common occurrence, especially for websites that have few authoritative trustworthy votes and try to make up for it by aggressive use of a phrase in the page content.
Google is a billion-dollar mega-enterprise helping people to find what they want, and as the online environment becomes more crowded, Google is becoming more sophisticated. You need to become more sophisticated too.
My philosophy has always been that PEOPLE read your Web site and that PEOPLE TAKE ACTION if they find your presentation compelling. If you’ve been using keyword -stuffing tactics it’s time to drop them in the trash where they belong.
Write for people. The search engines index for people. Let the search engines do their job, and you do yours.