StubHub has the unique ability to analyze ticket purchasing behavior for sporting events by sport and by state.

FORBES: Connect

As we have seen with Apple, consumers are becoming much more savvy about product upgrades and the associated timing, and purchasing behavior is affected.

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Female blogging communities also dramatically influence purchasing behavior, with over half of female blog readers reporting purchasing a product based on a blog recommendation.

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Online ad company DoubleClick, Abacus' former owner, scrapped plans to cross-reference data about consumers' purchasing behavior with their online habits in 2000, when privacy advocates howled.

FORBES: Consumer Spy

Having customers promote brands while buying them is a win-win situation and could potentially lead to incredible results, that is, if Amex and Twitter can get this new purchasing behavior to catch on with consumers.

FORBES: From Hashtag to Purchase: Twitter's Newest Partnership with American Express

Citing the rise of a new, moneyed middle class and changes in the purchasing behavior of consumers for Brazilian-made goods, Harvard Business School grad Reichel said now is the time to invest in a more online-attuned Brazil.

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Facebook, for example, correlates your online behavior with your purchasing habits offline.

CNN: The Internet is a surveillance state