Windows 7: Google Safe Browsing practices guilt by association.

If you were walking into a store and got mugged, would you immediately assume that it was the store's fault or the mugger's? What if you visited a Website and immediately got hit with malware? The two situations are essentially the same, but in the latter case, most people would blame the venue rather than the attacker. In the online world, however, Google's Safe Browsing service is pointing fingers at the attack venue, not the assailant.

On most small Websites, a third-party ad network delivers the ads. The site itself has no idea what the ad is or where it originated -- the ad network is supposed to handle that information. But bad ads still slip into ad networks, and in some cases, it can take the those networks days to find the culprit. Meanwhile, the site loses its reputation. If you were visiting a site for the first time and it gave you a virus, would you go back?