In a post dated May 23, Edelman stated that he had analyzed 88,388 current 180solutions pop-up ads and found that 4,678--or around 5 percent--of those ads included Google's AdSense ads. That is, for that 5 percent, the pages that popped up on users' screens contained pay-per-click ads served by Google.

The finding highlights the complexities of Internet advertising and the difficulties of policing ad-related policies, said Ari Schwartz, associate director of the Center for Democracy and Technology.

"It's basically an ongoing struggle," said Schwartz, in reference to enforcing adware-related policies. "You get rid of the problem one place and it sprouts up someplace else."

Although adware isn't in itself unlawful, Google prohibits AdSense participants from sending pop-ups that contain Google ads. A Google spokesman said that Google and 180solutions have no business relationship, and that the company is investigating whether its AdSense publishers violated the no pop-ups. "Web pages with AdSense ads that appear in pop-ups generated by 180solutions are against our policies. We take enforcement of these policies very seriously, and if we find any AdSense partners in violation, we take appropriate action," said a Google spokesman.

Daniel Todd, president of 180solutions, said this issue hadn't come to his attention before Edelman's posting. "If Google has rules that their folks are violating, we fully support them in enforcing their rules," he said.

He added that publishing clients of 180solutions could continue to use the service by arranging for the pop-up to be a page that doesn't contain Google text ads.

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