Better hope that inbetween reposting surveys and trolling for underage girls, you ran your Windows updates -


[QUOTE]
An online banner advertisement that ran on MySpace.com and other sites over the past week used a Windows security flaw to infect more than a million users with spyware when people merely browsed the sites with unpatched versions of Windows, according to data collected by Verisign.
[/QUOTE]

Brian Krebs @ Washinton Post dug a bit deeper and found that the ad used a WMF exploit that had been patched since January to install a trojan which invited its friends along.

The trojan plays pretty dirty, too:

[quote]
This stuff bombards the user with pop-up ads and tracks their Web usage. Only a little more than half of the anti-virus programs used at anti-virus testing service AV-Test.org flagged the various programs that the Trojan tried to download as malicious or suspicious.
[/quote]

Alternative browser users, alternative OS users and anyone with something better to do are relatively safe, of course.