Sure, I’ll agree that keyword density on a page has relevance – some relevance, not sure how much – but it is something to which I pay little attention, if any. This morning I was perusing posts at the Affiliate Summit Forum and read a thread asking, “Do You Track Your Keyword Density?”
My response was, simply, “I believe you should write for your readers and not for a (moving target) arbitrary set of numbers.” Enough said. That’s it.

Keyword Density: Is this too dense for effective Search Engine Optimization?
If you write narrative for your audience then everything else should fall into place. If you write something that is of interest to your readers and provides value for them – you will attract readers and search engine “recognition.” What is that value, you ask? It is simply something for which they (your potential readers) are looking. It could be a picture with a description of a place they want to visit, or have been – for the traveler. I could be a unique way of cleaning a paint roller – for the home remodeler. It could be a bit of humor for someone looking for online entertainment. It could be the best selection of checks available online – for someone needing to reorder checks. Provide “something” of value, that fulfills some sort of need, and you will have readers. Search engines follow the readers.
Search engines follow the readers? Huh? What’s that supposed to mean? I’ll bet you thought that search engines primarily dictate where are supposed to go (because of the order in which sites appear).
A search engine may index your site and temporarily give it a “good” position. Then it may seem to disappear. But if someone finds it – and likes it well enough to provide a link to your page/site – that can begin a (sort of) chain reaction. Search engines will “look at” whomever may follow that link (or links) and track HOW LONG they stay on your site once they get there. That simple metric is an indicator of how “relevant” your site (or page) is to a particular topic (set of keywords).
Keyword-density counters and/or manipulators can influence a page author to write in a stilted manner that chases people away. Poor narrative with a lack of good grammar and flowing thoughts will have people leave your site after a brief scan. They will NOT hang around to read more and that will actually hurt your chances at good search engine ranking.
If you write more for proper keyword density (a moving target for sure) than you do for your visitors, you will do more to hurt your search results than help them. Write for your audience – and you will have an audience.