Retailers are investing heavily to track consumers' behaviour in an attempt to work out what they might want to buy and how much they are willing to pay.
One factor behind disappointed expectations of America's performance could be the behaviour of consumers.
Driving the strategy of all these firms is the shifting behaviour of consumers. eBay's business, in particular, has been moulded by its users.
Most economists think that the CPI method is the right one, because its formula mimics the behaviour of consumers, who buy less of a product that is becoming relatively dearer.
So although another of the Office for Budget Responsibility's forecasting booboos was to anticipate faster growth in consumer spending than has materialised, ministers were well aware that they could not count on the behaviour of consumers to lead the UK back to prosperity.
Sometimes this leads to counter-intuitive behaviour, such as consumers preferring a flat all-you-can-eat fee when pay-as-you-go would be cheaper.
Critics suggest that this shrivelling of the supply chain leaves consumers vulnerable to bad luck or bad behaviour.
For example, American deregulation in 1978 has fostered some successful low-cost competition to the benefit of consumers while antitrust laws remain entirely dormant in restraining incumbent carriers from wasteful anticompetitive behaviour against this competition.
"As a responsible ISP, Virgin Media complies with court orders but we strongly believe that tackling the issue of copyright infringement needs compelling legal alternatives, giving consumers access to great content at the right price, to help change consumer behaviour, " it said.
BBC: Virgin Media attacked by opponents of The Pirate Bay block
"As a responsible ISP, Virgin Media complies with court orders addressed to the company, but strongly believes that changing consumer behaviour to tackle copyright infringement also needs compelling legal alternatives to give consumers access to great content at the right price, " the firm said in a statement.
"Ultimately, such behaviour is liable to slow down cross-border business and harm EU consumers, " it said.
But when half the market raises prices in just four days, consumers will question whether this is in response to volatile commodity costs or simply pack behaviour.
Businesses have sophisticated technology to monitor online behaviour, collect information about shopping habits and websites visited, and the services consumers have looked at.
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