These deceptive ads present a dilemma for Right Media, said Washington State Assistant Attorney General Katherine Tassi.

On one hand, Right Media is providing a service to publishers by giving them a way to exclude these ads, on the other, the services do expose "Right Media to some liability for essentially facilitating the transmission of deceptive advertisements," she said.

If Right Media simply dropped this type of filtering, it could make things worse for consumers by inadvertently encouraging unscrupulous advertisers to sneak their deceptive ads into the marketplace.

And enforcement agencies like the Washington State Attorney General are unlikely to hold ad networks, rather than advertisers themselves, accountable for deceptive ads, Tassi said.

One Web publisher said that while he thought that deceptive ads should be banned outright, he appreciated what Right Media is trying to do. "They are very forward when it comes to the kind of filters they allow you to use," said Sanford Liu, director of Interactive with Supernova.com, a music community Web site. "This is something that most other sites do not have."