At a hearing last month of the Senate Commerce Committee, some senators wondered aloud whether the use of behavioral profiling to target Web ads to users was overly invasive of people’s privacy.
While acknowledging the usefulness of online ad tracking in some instances, Senator Byron Dorgan, a North Dakota Democrat, likened behavioral targeting to someone following consumers from store to store, taking notes on what they did. He said he was concerned that the data trails left by users could create behavioral profiles that could follow them for years.

Senator Bill Nelson, a Democrat from Florida, compared concerns about targeted ads to those about federal wiretapping in a debate over the foreign intelligence surveillance act. “What I am struck with is that we [have] a similar issue here,” he said. “I use the Internet to go online to read the newspapers back home. If suddenly the kinds of articles I am reading . . . are going to be identified with me so someone can target advertising, I’m going to question the underlying basis of this.” The question, he said, is how to continue to allow the Internet to evolve yet also respect constitutional and civil rights.

At the hearing, a Federal Trade Commission official advocated voluntary self-enforcement of privacy rights, with the caveat that marketers should provide users with clearer disclosures. But Microsoft, Google, and Leslie Harris, president-CEO of the Center for Democracy and Technology, urged Congress to pass privacy legislation.

NebuAd President-CEO Robert R. Dykes also defended the privacy practices of his ad-serving firm. Mr. Dykes said that while his company sees every page consumers see, it tracks only “innocuous commercial” information and doesn’t keep any records on individual pages or Web sites seen.