Microsoft's initial warning, released Saturday, noted the compromised Hong Kong porn site, but also commented on the spread of the Trojan-dropping exploit to less prurient sites, including a Taiwanese search engine, later cleaned.
Microsoft estimated that 0.2 percent of the world's computers had been exposed to compromised sites, which number in the thousands.
The IE vulnerability is about as widespread through the browser's versions and iterations as possible. Microsoft's Security Advisory notes that the problem exists on:
"Windows Internet Explorer 7 on supported editions of Windows XP Service Pack 2, Windows XP Service Pack 3, Windows Server 2003 Service Pack 1, Windows Server 2003 Service Pack 2, Windows Vista, Windows Vista Service Pack 1, and Windows Server 2008. Microsoft Internet Explorer 5.01 Service Pack 4, Microsoft Internet Explorer 6 Service Pack 1, Microsoft Internet Explorer 6, and Windows Internet Explorer 8 Beta 2 on all supported versions of Microsoft Windows are potentially vulnerable."
The same advisory includes workarounds aimed at minimizing the risk.
Best way to avoid the risk, though, might be to shift to Firefox.