Some people argue that the broadband stimulus funds should not be spent until we have better mapping to tell us where the problems are. People at the local level know where the unserved areas are.
You never will ever meet a rural telco or rural cable operator that isn't painfully aware of locations where broadband isn't available by wire. Small communities aren't like big metro areas. People know each other, and that goes for anybody charged with providing broadband services using wires.
"Underserved" is a different matter. First you have to decide what that means, and what causes it. In some cases, lack of money, lack of PCs or lack of interest or knowledge are big issues there.
But lack of knowledge isn't the hold up in rural areas. Local people know where they need to get. Let them get there.