Having sent a pointed message to adware firms with its case against Zango, the Federal Trade Commission is shifting its focus to the advertisers that use "nuisance adware" firms to distribute their ads.

The FTC plans to send letters to advertisers to alert them that their ads have been distributed through Zango's adware, reports ClickZ, quoting one of the FTC's Commissioners, Jon Leibowitz, as saying the FTC is moving to pressure advertisers that enable "nuisance adware." He was speaking at FTC public hearings titled (awkwardly) "Protecting Consumers in The Next Tech-ade."

Advertisers "will take a look at this letter and be surprised," Leibowitz told ClickZ News. "You really need to move to the demand side if you want to stop the scourge of spyware, or nuisance adware."

The agency may not reveal the names of the advertisers who receive the letters, which will tell advertisers "how not to advertise in the future," Leibowitz said.