Internet users often receive Claria's advertising software – or adware – when they download other software, such as Kazaa. Often they ignore the messages on screen that explain what is being installed – so may be unaware that they have adware running their computers.
The software examines keywords, URLs and search terms in use on the user's browser and then selects which ads to display to that user. These ads often refer to competitors of the site being visited.
The Court of First Instance in Cologne, acting on a complaint by Hertz Autovermietung GmbH under Germany's unfair competition legislation, issued a preliminary injunction earlier this month.
The court ruled that Claria must stop "placing or allowing the placement of software-controlled automatic advertisements" on www.hertz.de without consent, "in particular in the form of pop-up and pop-under advertising windows."
Each violation of the injunction carries penalties of up to €250,000 or up to six months' imprisonment.
"Gator's unsolicited pop-up ads constitute an unwarranted intrusion that disrupts Hertz's ability to do business with on-line customers," said Remy Keijzer, General Manager of Hertz in Germany.
"We are gratified that the court in Cologne has recognized that Hertz and its on-line customers are harmed every time these ads appear, often without the full knowledge and consent of individuals who may have inadvertently installed Gator's spyware on their home computers," he added.
The decision in Cologne is the first court ruling in Germany related to so-called adware. It comes roughly three months after the US District Court for the Southern District of New York issued a preliminary injunction, ruling that similar software created by WhenU, another internet adware company, violated trademark laws in the United States.
That decision is currently being appealed before the US Second Circuit Court of Appeals and Hertz, which is not a party to the WhenU litigation, has filed a brief in support of the companies suing WhenU.
Claria has not yet commented on the ruling.
Microsoft, however, has been addressing the adware problem which, according to a recent Jupiter Research survey, people dislike more than spam. The Washington Times reports that the company is to include a pop-up blocker in its Internet Explorer browser which will be active by default.
