A grassroots effort by web developers is targeting users of adware program Zango and drawing a sharp response from the application's creator.

The campaign, apparently started by adult webmaster resource site Greenguy and Jim, centres around webmasters installing a script on their web page that detects Zango and redirects the user to a page warning them about the application.

The page, which has a large red biohazard sign next to the words "Zango Warning", tells users that their PCs have been "infected with ZangoSearch".

The site warns users that the application may try to log keystrokes and mouse movements and then says "We as a whole, believe this is a scourge that needs to be fought at the grassroots level. When you allowed this toolbar to be installed on your PC, you inadvertently agreed to allow Zango to do this to you."

Beneath the warning is a detailed description of how to remove Zango from a PC.

Zango spokesperson Steve Stratz called the Zango Warning site "blatant lies and scare tactics", and provided vnunet.com with a copy of an ad that the company will soon be running.

The ad, which is set to appear every time a user is re-directed to the Zango Warning site, tells the user "The Web page in question is designed to 'scare the surfer', as its 'creator' has confessed.

"We at Zango have gone to great lengths to ensure that every consumer who installs our software sees, prior to installation, a fully and conspicuously disclosed plain-language notice and consent process."

In a remote demonstration for vnunet.com, Stratz noted that Zango required the user to consent to installation of the program at least three times, and that Zango software was removable through Windows' uninstall control panel.

Zango has been at the centre of controversy over its practices in the past. In September, the company won judgement in a lawsuit alleging that Zango software was spyware.

The company took security software vendor Zone Labs to court in late 2005 over Zango being labelled as spyware by Zone Labs' security products. That suit was later dropped. McAfee labs designates Zango as a " potentially unwanted program".

Earlier this year the Center for Democracy and Technology filed a complaint with the Federal Trade Commision (FTC), alleging that Zango engages in unfair and deceptive business practices.

The makers Greenguy and Jim did not return a request for comment.