Consultant Ben Edelman faulted Yahoo for not letting its advertisers know where their ads might end up.
"We know people pay very high pay-per-click fees when they think they're getting traffic from Yahoo, because advertisers think Yahoo users are more valuable," Edelman told internetnews.com. "Whatever their value actually is, advertisers who are buying the stuff should be told what they're getting."
Adware is free ad-supported software that users can download at no charge. But in his blog, Edelman documented how the software is installed without clear notification.
Edelman claims three bad actors distribute Yahoo Search Marketing ads: Claria, eXact and DirectRevenue.
Edelman said that users may unwittingly install Claria's tool, which delivers pop-up and pop-under ads targeted to users' search activities. He documented dozens of instances of software from eXact Advertising installed through security holes, with no notice or consent; eXact displays a sidebar to search results displaying targeted ads. DirectRevenue's Searchblazer delivers pop-up ads based on users' search queries.
According to Edelman, DirectRevenue has the worst practices. It may use misleading pop-ups to get users to install it, and it's unusually difficult to remove. Worse, he said, it can disable and delete other software on a user's PC.
Yahoo should inform advertisers that their messages may end up displayed in adware applications that don't use proper business practices, Edelman said. He noted that Google (Quote, Chart) also distributes PPC ads to adware companies.
Yahoo did not respond to a request for comment; eXact did not respond to a request for comment and internetnews.com was not able to reach DirectRevenue.