Online Data Present A Privacy Minefield



But Chris Hoofnagle says that may be futile. As the head of the privacy programs at the University of California, Berkeley School of Law, he's been tracking the information economy for some time, and he says it's getting harder to make informed decisions.

"As there's been growing awareness of how commercial data brokers operate, they've become more secretive," Hoofnagle says. He says big data brokers are telling the public less about the provenance of their data — where they're getting their information — and he's been tracking this change by saving screenshots of those companies' Web sites.

Data Companies Go Private

As an example, Hoofnagle pulls up screenshots of a big database called Batch Trace, now owned by LexisNexis. As recently as 2002, he says, the site listed the kinds of business that supplied it with data, such as call centers and pizza delivery companies.

"As time goes on, this gets thinner and thinner," Hoofnagle says. "By 2006, the provenance is gone."

A representative for LexisNexis, Nick Ludlum, says the company changed its provenance information for marketing reasons.

Hoofnagle says another reason may be politics.

"If consumers knew the extent to which this data was being collected and repackaged, there would be riots in streets," Hoofnagle says.