PALO ALTO, Calif. ( TheStreet) -- With America splintering into homogenous localities of like-minded individuals, would a Web site directing those people toward one another really serve the greater interest? No, and that's exactly why consumer site LikeMinds exists.

Launched last August by Georgia Tech and Stanford University computer science alum Alan ElSheshai last August, LikeMinds allows users to copy their product ratings to different services and generates product recommendations based on those ratings. Once the ratings are compiled from Amazon ( NASDAQ), Apple's ( AAPL) iTunes, Netflix ( NFLX), Blockbuster ( BBI) and other sites and transferred, they can be analyzed against those of other users, geographically mapped and placed into bar charts and Venn diagrams showing consumers what they normally buy and what they'll likely purchase in the future based on the tastes of folks just like them.

"It takes a lot of time to catalog your preferences; both to find items and recording your opinion of them," ElSheshai says. "After a user has gone through the trouble of doing this once, they typically don't want to do it again."

Nor do marketers, companies and even civic institutions want to go parsing through data on various sites when it can be collected in one place. For Wal-Mart ( WMT), which just purchased Web video streaming service VUDU, information on Netflix and Amazon video viewers' preferences could be invaluable to a potential movie service and existing retail operations. LikeMinds' geographic data, meanwhile, could dictate not only where a user lives or who they date, but where stores, services and even religious centers set up shop.

"We sort geographically as consumers because it makes it easier to get the stuff we want," says Bill Bishop, co-author of The Big Sort: Why the Clustering of Like-Minded America Is Tearing Us Apart. "As consumers glom around others with similar wants, everyone is more likely to see the movies they want in the local theaters, listen to the music they want at the local club, worship at a church that fits, eat the foods you like."

Bishop, who co-wrote his book with retired University of Texas sociology professor Robert Cushing, notes that mega-churches in the 1970s used missionary Donald McGavaran's "homogenous unit principle" to build churches whose language, food, music and even style of dress fit a certain cultural type. Marketers caught on as well, with a paper in the 1973 issue of the Journal of Advertising headlined "Are Grace Slick and Tricia Cox Nixon the Same Person?" and positing that buyers were breaking down into "image tribes" and should be pursued as such.

However, with the advent of blogs, social networking pages, YouTube videos and consumer ratings, those "tribes" are being whittled down to the individual level. While such services are allowing consumers to make more of their information public, they're also creating a lot more data for retailers to disseminate -- making a clearinghouse such as LikeMinds much more valuable.

"It's clear there is an appeal to marketers and companies for this type of preference information, but when users are in control of who has access to their information, companies must provide clear benefits to users before a user will share that information with the company," ElSheshai says. "On many sites, marketers are benefiting more than consumers, and we think it should be the other way around."

Though consumers and marketers may get what they want out of a LikeMinds-style data exchange, the results have been mixed-to-discouraging on a broader scale. Cultural divides once reduced to differences of opinion between Red States and Blue States or other similarly broad swaths of America now appear on far more local levels.

Bishop says Americans' abandonment of a society led by groups like chambers of commerce and unions for one of individuals lead to localities where issues like what to study in local schools or where it's appropriate to carry firearms are settled among a like-minded citizenry. When bigger, national issues arise -- energy, health care, immigration -- that system can break down based on a limited understanding of different individuals we never see. Though ElSheshai says more users have requested more social features for LikeMinds, Bishop says that may lead to more cultural clustering akin to modern political gridlock and that no amount of information shared among like-minded people can change it.

"We sort socially because we want our surroundings to reinforce our sense of ourselves -- which is, these days, the most important, vital work that we do," Bishop says. "If there is a new trend here -- and by new, I mean in the last two generations -- it is the overwhelming need we have to write the story of our own lives, to become our own works of art."

-- Reported by Jason Notte in Boston.
Jason Notte is a reporter for TheStreet.com. His writing has appeared in The New York Times, The Huffington Post, Esquire.com, Time Out New York, The Boston Herald, The Boston Phoenix, Metro newspaper and the Colorado Springs Independent.