I recently had the privilege of sitting down and speaking with Jakob Nielsen. Known as one of the foremost usability gurus in the world, Jakob showed me that he also has a keen understanding of SEO. As the world of web marketing matures, it will be increasingly obvious that you can't do long term SEO without considering usability at the same time.
One of the most interesting aspects of this is the use of keyword research tools. SEOs routinely use these tools to find the highest volume keywords people use related to the site they are currently working on. Often, we think of this as a purely mathematical numbers game. We see the highest volume keywords, and related words, and put them in the title tag, a header at the top of the page, and work some references into the text on the page.
Sounds like a straight forward concept. However, there is far more to it than that. The reason why some keywords are more popular than others is because those keywords reflect the most common way users think about their topic matter.
Placing these intelligently on the page does far, far more than just help you get search volume. It also tells the user that they have arrived at the right place to get what they want. Ultimately, keyword research should be more than an SEO exercise - it needs to be a usability exercise as well.
Once you have the keywords you are interested in, you can place them, and related words in key elements of the page. You can also provide your copy writers with general guidelines for how to produce copy for the page.
I always prefer to give the writers high level instruction, rather than trying to micro manage keywords into their text. Ultimately, telling them that the article is about "Circular Red Widgets", and how they are better than "Square Blue Widgets", is about all the instruction you should provide.
Then let them write a solid piece of quality content. The article quality will drive conversions, in addition to links and search engine traffic, making it a win-win-win situation.