Internet portal Yahoo shut down its user-created chat rooms after a television news series showed the online service used in apparent attempts to exploit children for sex.

Yahoo spokeswoman Mary Osako would not say whether the decision was in response to the series on Houston television station KPRC that showed online discussions bearing titles such as "9-17 Year Olds Wantin' Sex" and "Girls 12 and Under for Older Guys."

Some of Yahoo's advertisers, such as PepsiCo Inc. and State Farm Insurance Cos., said yesterday that they pulled their advertising from the site because of the series.

"We were completely unaware that our ads were associated with these chat rooms in any way," PepsiCo spokesman David DeCecco said. "As soon as we found out, we worked with Yahoo to remove them immediately from the site."

State Farm spokesman Phil Supple said his company was shocked when his company saw where some of its ads were appearing in Yahoo. Supple said the company ceased advertising with Yahoo in April as the TV station was preparing its report but resumed after it was assured that State Farm spots would not appear on chat-room pages.

Osako said the decision to close the chat rooms, which were online discussion sites that any Yahoo user could create, was made because the company is working on a better version. "We are working on improvements to enhance the user experience and compliance with our terms of service," she said.

Yahoo's "terms of service" agreement says users must agree not to use any of the company's products or services to "harm minors in any way" or to e-mail or transmit content that is "vulgar" or "obscene."

The company did not say yesterday when the service will return or how it will operate when it does. Yahoo still lets users participate in online chat rooms that the company creates.

"Yahoo chat was never where kids should be," said Parry Aftab, executive director of WiredSafety, a Web site that promotes online safety for children. Aftab said she would be happy for the company to bring the service back if there were a way to keep children safe. "Yahoo has always cared a lot about these issues, but they've mostly worked behind the scenes," she said. "If there's anybody I would trust to do this right, it would be them."

This is not the first time Yahoo's image has risked tarnish by people seeking to lure children or to trade pornographic material involving minors. A 2001 FBI investigation targeted certain Yahoo users and resulted in the arrest of more than 100 people in the United States.

Yahoo didn't say when it might bring back user-created chat rooms.