What sources and techniques can be utilized to attain and maximize this objective!
I don't know if this is the sort of thing you have in mind...
But in usability circles, they talk a lot about the concept of "personas". Basically, when you're trying to make your site more usable, you're supposed to imagine a specific
individual using it -- not generic, like "an older person who's not vary familiar with computers" or "a teenaged boy who's into gaming", but really REALLY
As described on Jared Spool's site, UIE.com, in an article entitled "Personas: Matching a Design to the Users' Goals" by Christine Perfetti: "A persona is a profile of a typical user; it is a description of an archetypal user synthesized from a series of interviews with real people and includes a name, a social history, and a set of goals that drive the design of the product or web site."
Notice they go so far as to recommend that you construct a name and social history for your personas. I told you, they're SPECIFIC.
You can have more than one persona. In fact, you should have one for each class of user. The trick is to make useful divisions into classes so that you've covered each basic type of visitor you have (or would like to have) but not so much that you've got dozens of personas. Then you start making up specific individuals to represent each of those classes.
If it works for usability, why couldn't it work for SEO and marketing? The more you know about the people who are visiting your site (or the people you'd like
to have visiting your site), the more it would seem to me you could determine a copy style that they would find appealing, locate search terms that they might be likely to use, identify sites that they might be likely to visit (from which you could try to obtain links or reviews or on which you might advertise) and so forth.
Just an idea...
As usual, YMMV.