When we go through an electronic toll with our E-Zpass, a record of our movements exists that might one day be used in a divorce case.

But in some cases, one marketer's owned media become another marketer's paid media—for instance, when an e-commerce retailer sells ad space on its Web site.

Tomas Bella of Piano, the company operating the scheme, says this suggests that readers will pay for content, “but only when it is convenient enough”.