Keywords are the key that unlocks your website for your prospects. When you optimize your web 
content for the right keywords, people who are searching for what you offer can find you. While some of this can be structured into the framework and backstage parts of your website, the actual copy that appears on the page is critical to having a high search engine profile.
Remember, however, that you must also have copy that communicates the right message. Jennifer Laycock over at Search Engine Guide has a nice article on tweaking your copy, not just for SEO, but to make sure that you are actually communicating the information and tone that you need and want them to receive.
This is a great illustration of high quality content does double duty. It both drives traffic, and it drives conversions.