From Kapersky:

There appears to be multiple ad networks redirecting to Blackhole sites, amplifying the mass exploitation problem," Kaspersky Lab expert Kurt Baumgartner wrote. "We have seen ads from legitimate sites, especially in the UK, Brazil, and Russia, redirecting to domains hosting the current Blackhole implementation delivering the Java 0day. These sites include weather sites, news sites, and of course, adult sites.

Critical Java zero-day bug is being “massively exploited in the wild” (Updated) | Ars Technica

Even the latest versions of Java are vulnerable. This hack allows keyloggers and even screenshots taken of your passwords. If you haven't gotten an ad-blocker or disabled your Java, best to do it now. Especially if you go to those sites.