Don't titles rule! 'Extremely Critical' Flaw Threatens Internet Explorer Users was announced a few days ago. In that article, it tells users that "Microsoft is recommending that users turn off the "Drag and drop or copy and paste files" option in Internet Explorer and set security levels to high for the Internet zone."
A thread at WebmasterWorld discusses how this "security fix" recommendation by Microsoft, will make Google AdSense ads invisible to those who take this route. Of course, the rumors begin that Microsoft did this to try to hamper Google's AdSense revenue. :)