If you are selling a specific product or set of products, then you should be trying to corner as many related search phrases as possible. For example, if your blog offers information on pet fish and you would thus like to sell "pet fish" related products on your site, then you should try to post as much related content to your site as possible.
In the case of pet fish, you would do well to corner such search phrases as "cheap fish tank", "affordable fish food", "fish tank cleaners", etc. In order for Google to associate such phrases with your site you would need to literally have these phrases posted somewhere on your blog or website. Also, it would help to have articles circulating on the web that you posted, which are related to these search phrases both for manual traffic leads as well as for PR juice.
Using Spinbot, you could spin articles, paragraphs or single sentences containing these phrases. If you needed to preserve certain words to keep their strategic placement in your blog or website, then you would enter them in the "Ignore" field by typing in "tank, clean, affordable," etc. Chances are, however, that you would do just as well letting Spinbot rewrite these words to expand your phrase coverage in excess of what you had planned.
In general, the goal is search phrase optimization. Google and other major search engines will investigate the density of certain phrases or words on your site to verify your site's relevance. If your goal is to corner the pet fish market, then you should cover all things "pet fish" related somewhere on your site, most likely more than once.
Much of the challenge here comes from the fact that it takes time and effort to create quality, readable content for your blog. But this is where Spinbot comes in to help you out: You can use Spinbot's advanced text rewriting capabilities to create new, reworded content from your existing content. This will expand your search-engine-optimized phrase coverage as well as the overall volume of content on your site, which gives you additional opportunities, or "hooks," to be indexed and thus attract visitors via organic searches for the service or product you are providing.
Have you tried Spinbot yet?