After the company decides on the city-by-city allocation of its budget, it can refine each city allocation
down to census tracts or zip4 code centers. Census tracts are small, locally defined statistical
areas in metropolitan areas and some other counties. They generally have stable boundaries
and a population of about 4,000. Zip4 code centers (designed by the U.S. Post Office) are a little
larger than neighborhoods. Data on population size, median family income, and other characteristics
are available for these geographical units. Using other sources such as loyalty card data,
Mediabrands’s Geomentum targets “hyper-local” sectors of zip codes, city blocks, or even individual
households with ad messages delivered via interactive TV, zoned editions of newspapers, Yellow
Pages, outdoor media, and local Internet searches.