Remember how when you were high school everybody would segregate themselves in the lunch room? The cool kids would sit at their table, the dorks at would sit the table that was wobbly, the skateboarders would crowd in on one or two tables, and the goths and punks would sit in the back (either fantasizing about going vampire on the high school populace or turning it into a giant mosh pit, depending on their proclivities). OK, so maybe that was a little too stereotypical, but you get the point.
You would have thought that there was assigned seating, but there wasn't. Dorks that sat at the cool table (unfortunate miscreant) would usually get picked on until they left. We chose to segregate ourselves willingly and reinforced it socially. It turns out, or so marketers believe, that we still do this as adults. We all know about the realities of "white flight", "urban decay", and "urban gentrification", at least.
Think about your neighborhood. Can you construct stereotypes of the types of people that live there? If you can't (but you probably had no troubles doing so, being the intelligent reader that I know you are), Nielsen certainly can. Nielsen's PRIZM marketing research tool profiles the consumers in every ZIP code region of the glorious United States, grouping them into clusters like Money & Brains, Suburban Sprawl, and Shotguns and Pickups. There are 66 clusters in all, and Nielsen provides a handy Prizm Code for deciphering their meaning. The clusters are grouped into 4 main categories (Urban, Suburban, Second City, and Town & Rural), with numerous subcategories. Breaking down markets like this is commonly referred to as market segmentation, and it makes it easier for businesses to figure out where to sell their goods and where their advertising money would be used most effectively.
According to Nielsen, the aforementioned Shotgun and Pickups cluster (named as such, Nielsen explains, because they own more shotguns and pickups than any other cluster) is likely to shop at Lowes and own a horse and a Dodge Ram. The Upper Crust, the most prestigious cluster, enjoys spending thousands of dollars on foreign travel, reading the Washington Post, watching the Golf Channel, and driving Aston Martin D89s. My personal favorite cluster is Bohemian Mix, which buys Spanish/Latin music, read The Economist, and watches soccer. Beneath the title is a drawing of a husky Hispanic man serenading a woman (presumably another man's wife) with his guitar. Obviously, these are just extremely simplified examples of the sort of detailed marketing information PRIZM makes available to businesses that pay for service. And scarily enough, even these simplified examples seem to contain elements of truth in them.
I'm not exactly sure how Nielsen goes about developing these clusters, but I can only imagine that they will get more and more accurate with the emergence and widespread adoption of the internet and smartphones, both of which make tracking the actions of consumers easier than ever before. PRIZM is part of a broader movement to develop psychographic profiles of consumers, which basically attempt to predict the way consumers will shop by creating consumer profiles for their personality types (so that they can expose depressed people to more ads for alcohol more efficiently, and things of that nature).
On their web site, Nielson provides a ZIP Code Look-up tool for its PRIZM database that can bring up a list of the types of clusters that exist in any ZIP code as well as a page that provides more detailed definitions of the various clusters.