AudienceScience has also taken down a from MEC, which has placed ads for AT&T.

AudienceScience decided to take down the references to AT&T because of the confusion over its use of behavioral advertising, Hirsch said. "We wanted to make sure we conferred with all the appropriate parties to have consistent messaging," he said. "There were, what I feel to be, some confusing comments made ... about the situation."

AT&T spokesman Michael Balmoris said Attwood was talking about AT&T's role as an ISP, not an advertiser, when she said Thursday that the company does not use behavioral advertising.

"As an ISP, we do not track our customers' data across unrelated Web sites to create a profile for behavioral advertising, or hire other firms to do so on our behalf," he said. "Our relationship with this firm is as an advertiser of AT&T products and services. News reports suggesting that we are engaging in behavioral advertising by selling information of our customers is flat wrong."

AT&T does not control the practices of the ad networks or search engines it places ads with, but it has disclosed in the past that it advertises with those outlets, he added. "Like thousands of other businesses that operate websites, AT&T does business with advertising networks and has partnered with providers of online search," Attwood said in an August letter to Congress.