Demographics don’t work in social media communication - which is a blessing as they’re completely inefficient in a complex world of niches linked by common-interest.

I’ve long pushed clients away from thinking of their audience as simply eyeballs and demographics. Even more complex segmenting of their audience can still miss the mark. In social media the trick is to find the point of connection between a brand and its target audiences passions and interests, and then build a mutually beneficial relationship over a period of time.

With this in mind, it was pleasing to see AdAge point to some more detailed research backing up my long held assertion:

The 2010 Census is expected to find that 309 million people live in the United States. But one person will be missing: the average American.

“The concept of an ‘average American’ is gone, probably forever,” demographics expert Peter Francese writes in 2010 America, a new Ad Age white paper. “The average American has been replaced by a complex, multidimensional society that defies simplistic labeling.”

The message to marketers is clear: No single demographic, or even handful of demographics, neatly defines the nation. There is no such thing as “the American consumer.”

The census is the biggest market-research project of the decade. The Census Bureau will spend upward of $15 billion to count the population as of April 1, 2010, and amass a treasure-trove of data on U.S. consumers.

“The decennial census will tell us quite precisely how American consumers have changed in the past decade,” Mr. Francese writes. “It also will give us clues about where the consumer marketplace is moving. The census is the gold standard against which the results of all major consumer-research studies are benchmarked.”

The Census Bureau will begin releasing data in spring 2011. Mr. Francese, demographic trends analyst at WPP’s Ogilvy & Mather, New York, and founder of American Demographics magazine, now offers projections and insight on what the census will show.

His 32-page report, available at AdAge.com/2010America, will give marketers a window on what the census will show and how to adapt those findings in a marketing world reliant on broadscale demographics that no longer exist.

Selected findings of 2010 America:

• U.S. households are growing ever more complex and varied.
“This census will show that no household type neatly describes even one-third of households,” Mr. Francese writes. “The iconic American family — married couple with children — will account for a mere 22% of households.”

The most prevalent type of U.S. household? Married couple with no kids, followed closely by single-person households, according to Mr. Francese’s projections.

The Census will give Americans 14 choices to define household relationships. Mr. Francese says this will “enable the Census Bureau to count not only traditional families but also the number and growth since 2000 of blended families, single-parent families and multigenerational families, as well as multiple families doubling up in one household.”

That presents boundless opportunities for marketers and media in how they target and segment households.

• Minorities are the new majority. “One fact says it all,” Mr. Francese writes. “In the two largest states (California and Texas), as well as New Mexico and Hawaii, the nation’s traditional majority group — white non-Hispanics — is in the minority.” And in the nation’s 10 largest cities, he says, “no racial or ethnic category describes a majority of the population.”

Mr. Francese notes how diversity varies greatly by age, “with the younger population substantially more diverse than the old.”

To quote Don Schultz from his excellent keynote on media consumption at the recent iMedia Summit: “18-35 year old women? I’ve been with 18 year old women and I’ve been with 35 year old women… and let me tell you they’ve got nothing in common!”