Consumer Alert: Stealth Ad Invasion

Don't look now, but your computer may be harboring software that lets unwanted advertising in.

Feel like online ads are getting more annoying? You're not alone. Consumer advocates are up in arms over adware--a new class of advertising products that typically install on your PC as part of a software download. Once it's there, adware does tricks like putting commercial links and ads on Web pages you visit--without the site's consent.

Recent adware controversies have centered on Gator and Ezula, two firms that bundle their adware with dozens of popular programs, including the game Snood, utilities like WeatherBug, and file-sharing software such as Kazaa and AudioGalaxy Satellite.

Gator covers banner ads on a site with ads from its clients. The program also sends periodic reports to Gator's server about the Web sites you've visited and the ad banners you've clicked, so Gator can favor you with ever-more-relevant ads. According to the company's lengthy privacy policy, the data Gator collects is anonymous and will not be sold.

Ezula's TopText, in contrast, works by overlaying hyperlinks onto whatever Web page you're viewing. While visiting ESPN.com, for example, you might see a yellow TopText link on the word football that, if clicked, would take you to a competing sports site.

The trend shows few signs of abating. Ezula and Gator say that their advertisers are very pleased with results, and they claim that millions of PCs have loaded the software.

PCWorld