I did a Google search for Windows 7 this morning and every link on the result page says "This site may harm your computer". If you click a link that says that, you get an interstitial page that says the site could harm your computer but precious little else.
A few minutes later, another Google search for something else said the same thing. And getting past the error if you want to get to the site is really a pain.
Even scarier to me, a search for "Pittsburgh Post Gazette" says the same thing about our site here, but there's nothing out of kilter with our site that I can find.
This is the danger in a web search monopoly. Google's obviously got a problem this morning, but the end result is that people's perceptions about those sites could be tarnished. And for no good reason.
UPDATE: Google has apparently found the problem and fixed it. Whether they'll own up to it or not is a different story. We'll wait and see what happens.