Clicking on a paid link in a results page displayed by Google, Yahoo and other search engines is two-and-a-half times riskier than using an "organic" link, according to McAfee.
Despite this, security software vendor said the%age of dangerous sponsored links has fallen in the last six months.
Changes Google made last year to its AdWords paid link program are behind the improvement, said Mark Maxwell, senior product manager for McAfee SiteAdvisor, a free safe-browsing service.
"Organic search results have pretty much stayed consistent," said Maxwell, "but sponsored search has improved pretty dramatically."
Sponsored links - those paid for by online advertisers who hope to lead users from search results -- are still more likely to pose a risk, but things have improved.
Last May, SiteAdvisor said 8.9% of all paid links were potentially dangerous, while six months ago, the figure had dropped to 8%. Data from last month, said Maxwell, now pegs that number at 6.9%.
"That's largely attributed to Google taking several steps," he said. "It's been a little bit tougher on advertisers who want the prime spots on the page, and its association with StopBadware.org has also helped."
Google, along with other technology companies such as Sun Microsystems Inc. and Lenovo Group Ltd., helped launch the malicious site clearing house last year.
Because AOL and Ask.com also use Google's paid listings, the risk factor for their sponsored links also decreased. Only 4.4% of AOL's sponsored links, for example, were judged dangerous by SiteAdvisor in May, compared to 8.1% in Nov. 2006 and 10.2% a year ago.
Modifications to Microsoft's Live Search and Yahoo, however, were less successful. "With the exception of Microsoft, we've seen slight improvement across the board in organic search," said Maxwell, referring to non-paid links. Six months ago, 2.6% of Live Search's organic results were classified by SiteAdvisor as risky; last month the number had climbed to