In other words, how do you get people to start searching for a problem that they didn't know they had, that you solve? Constant Contact went through this in the late-nineties; nobody hit Google and typed "email marketing software," because it didn't exist. CC was able to establish themselves as a thought leader and foster a demand for their product. What are some best practices in this realm?
Identify your target demographic. Anticipate their online search behavior. Be where they go.
This can be done effectively with a mixture SEM and domain strategy. Focused ad placement within published websites and forums may also be a good -- if more labor-intensive -- solution.