SiteAdvisor helps protect you from all kinds of Web-based security threats including spyware, adware, spam, viruses, browser-based attacks, phishing, online fraud and identity theft. Our automated testers continually patrol the Web to browse sites, download files, and sign-up for things with e-mail addresses. As you search, browse, download or register online, SiteAdvisor's safety ratings help you stay safe and in control.If you register as a preview tester and download SiteAdvisor's software (not yet in general release) you'll be hooked into their network via a browser plugin; you can get SiteAdvisor's ratings on most popular sites before you visit, and check out most downloads before you download something and possibly challenge your computer's "immune system" (antivirus, anti-spyware software... you're all running this stuff, right? Right?)
Over at the Site Advisor blog, they're starting to publish the results of their research. It ain't pretty.
When we first started crawling the Web looking for bad downloads last year, we weren't sure what we'd find. Today, a million Web sites and 140,000 download tests later, I can say with confidence that there are some great programs to be downloaded out there. I can say with equal confidence that there's also plenty of train wrecks waiting to happen to your PC.