Once on the page, the user is instructed to scroll to the end of the page to remove their email address. If the mouse is used for scrolling, this will trigger the drag-and-drop exploit which then automatically downloads and executes a malicious executable.
Examples seen in the Fall of 2004 are downloading a file named windows-update.exe which has been found to be the Backdoor.Win32.Agent.ce trojan. Of course, the actual trojan downloaded - as well as the filename used - may and likely will vary. Additionally, infection cannot be diagnosed based on filename alone; there may well be instances of perfectly legitimate, non-infected files bearing the name windows-update.exe.
In summary, in addition to validating an active email address and thus increasing the amount of spam received, the opt-out link may also be a ploy for enticing users to visit booby-trapped websites. Of course, this pertains to unidentifiable and unsolicited spam. Mailing lists and other email correspondence to which the user has intentionally subscribed would not be considered at risk.
If you feel you may have been the victim of the 'opt-out' ruse, use up-to-date antivirus software to scan your system and remove any infections found.
