Documents that The Register describes as “highly classified information about human traffickers from the Dutch Royal Marechaussee - a service of the Dutch armed forces that is responsible for guarding the Dutch borders” have shown up on Kazaa.  A working theory is that they were (inadvertently) shared because they were deposited into a Kazaa-shared directory.

Shades of hard drives being left in public places.  Once again, the security issue appears to be the user and not the technology.