The prospect of new laws raised hackles at the Interactive Advertising Bureau, which represents the online-ad industry.

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The Interactive Advertising Bureau, whose members are responsible for most online tracking, said the bill gave too much discretion to the Federal Trade Commission.

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"The days of dumb advertising are over, " Randall Rothenberg, the President and CEO of the Interactive Advertising Bureau (IAB) told me over breakfast at Stream.

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Sheryl Draizen, general manager of the Interactive Advertising Bureau, a trade group representing online advertisers, said that "obviously it's great that Nielsen is innovating" and agreed that time spent on a site is a crucial metric.

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Take, for example, a 2012 study from the Interactive Advertising Bureau, in which 76% of consumers said they used their mobile phones in-store to help make a purchase decision, and more than half (53%) abandoned an in-store purchase because of information they found, such as lower prices or a negative review.

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