I caught up with an old friend/client who runs three business locations in Manhattan - downtown, midtown and uptown. It turns out that even within that small area, the effectiveness of various media is different.
Downtown people are more susceptible to online, midtown density lends itself to outdoor and uptown needs the direct marketing route. The customers are similar but their environments and lifestyles are different.
It's a good reminder that aggregating an audience geographically can be as naive as doing it demographically.