"Right now, there is behavioral targeting in the online environment, and it is by Web actors who don't have direct customers to answer to," she said. "The disadvantage [of a Web advertising model] is that your customer is your advertising industry, it's not our customers."

Customers will be confused if ISPs and Web sites have different privacy rules, Attwood added. "When the customer turns on a computer and goes to a Web page ... I can't do anything to protect that customer from being tracked by other entities who are not at this hearing," she said.

Senator Byron Dorgan, a North Dakota Democrat, noted there's already customer confusion about privacy protections online. A poll released Thursday by the Consumer Reports National Research Center, shows that 61 percent of respondents are confident that their online activities are private and not shared without permission, and another 57 percent incorrectly believe that companies must identify themselves and indicate why they are collecting data and whether they intend to share it with other organizations.

Forty-eight percent of those polled incorrectly believe their consent is required for companies to use the personal information they collect from online activities, Dorgan noted.

Dorgan asked the ISPs what information they now collect about their subscribers unrelated to targeted advertising. AT&T does collect "lots of information" for purposes such as improving service, Attwood said, but she didn't elaborate further.

While the ISPs and some committee Republicans called for ISPs to create their own privacy guidelines, Gigi Sohn, president of consumer advocacy group Public Knowledge, called herself "the skunk at the self-regulatory party."

The ISPs suggested competitive pressures will force them to stick to privacy best practices. Sohn disagreed. "The problem is, at least in broadband, that there isn't that much competition," she said. "The notion that there's going to be this competitive pressure -- I'm dubious."