Web search just got safer, at least on Yahoo! -- with Yahoo! joining hands with McAfee to offer security alerts warning users against potentially dangerous Web sites.

How do these alerts work? A red exclamation mark or some other warning sign shows up next to malicious links identified by McAfee as 'dangerous downloads'. Once put down as malicious, Yahoo! claims it completely blocks the harmful Web sites from showing up during user search. So what constitutes 'dangerous downloads'? Adware, spyware, and other malicious programs that can be used to hack or crash computers.

What is the technology used? McAfee claims it is a stripped-down version of its full SiteAdvisor technology that is available for free download from the company Web site. Which uses red, yellow, and green icons to distinguish between safe and harmful sites. In addition, McAfee SiteAdvisor has a premium version that adds other features to the software at a price. The new service is operational beginning today.