EWeek.com, a technology news site owned by Ziff Davis Enterprise, in February displayed an ad on its homepage masquerading as a promotion for LaCoste, the shirt maker. The retailer hadn't placed the ad -- a hacker had, to direct users to a Web site where harmful programs would be downloaded to their computers, says Stephen Wellman, director of community and content for Ziff Davis.
Similar attacks occurred across a series of News Corp.-owned sites in February, including AmericanIdol.com, FoxNews.com and IGN.com. In January, clicking on an ad on Major League Baseball's MLB.com led visitors to a site with malware.
Safety tip: Don't click those ads, even if the offer is enticing. Go directly to a company's site if you're truly interested in their products. If you don't know how to find the company's site, do a Google search.