As far as I can see the SEO matter, I have to say that Kerolina's point of view is right. I think it's true that while some just deal with researching on keywords, others are strategic at submitting content to relevant directories for link building purposes. There are also those that offer counsel on redesigning the present features that make a site stall and improving them with others that can bring more visibility and higher ranking. One can also find those that offer all these services all in one package.
And it's not all about SEO, of course. For example a good way to help your SEO is, for example, to bookmark your websites.