Earlier this months several members of Congress signed a letter to 33 leading Internet and broadband companies including Verizon, AT&T;, Time Warner, Comcast, Microsoft, Google, and others, pressing them for information about the extent to which they collect information about consumers' use of their broadband services or websites.

Apparently, some are collecting quite a bit.

Cable One, a large cable operator in the Phoenix, Arizona area, says it conducted a six-month trial of new technology that tracks consumers' Internet habits and custom tailors ads, to make them more relevant. Several other cable operators and Internet service providers (ISPs) responded with letters saying they have, or plan to, run similar tests.

Meanwhile, AT&T; told the lawmakers its concerns are misplaced, insisting that Google's online ad networks are much more invasive than anything the ISPs are planning. But the members of Congress say any erosion of privacy on the Internet is a cause for concern.

"Privacy is a cornerstone of freedom. Online users have a right to explicitly know when their broadband provider is tracking their activity and collecting potentially sensitive and personal information," said Rep. Edward J. Markey (D-MA), chairman of the House Subcommittee on Telecommunications and the Internet.

"New technologies, such as 'deep packet inspection' technologies, have the ability to track every single website that a consumer visits while surfing the Web. This sweeping ability to collect, analyze, and profile how individuals use their broadband connection raises clear privacy issues and I believe such activity should occur only with the express prior consent of individual citizens."

Markey also said individual websites and search engines and their affiliates that monitor users also owe consumers constructive notice of such activities and the right to limit or thwart any personal data collection.