Well... to answer your question about defamation, it has to be done in the media, or in front of witnesses who can attest to it. It won't work if it happened in private.
As for posting a video on Kazaa... c'mon, you don't have to be a genius to avoid having legal trouble afterwards... Remember the Star Wars Kid, as well as the movie Trainspotting. As long as you have taken care to deny plausibly that you had anything to do with that video becoming public, and that someone else (no idea who that was) took it from you and posted it, there's not much that can be done about it.
Mind you, these are my interpretations of current U.S. media laws, based on courses I took in the field. They do not condone any action you might take, and should not be considered an encouragement towards revenge.
Although, having gone through something like that myself many years ago, I have to agree that revenge, while arguably not the best course of action, and morally reprehensible, is nevertheless the only thing that guarantees satisfaction. If you can be Gandhi-esque enough to leave it all be as it is and turn a new leaf, fine. Otherwise, you can definitely request a meeting with the head of the graduate studies at her school and give out the information you posess (in the most calm and dry/professional manner you can muster), and even play pranks with other stuff you might have in your posession.
As for posting a video on Kazaa... c'mon, you don't have to be a genius to avoid having legal trouble afterwards... Remember the Star Wars Kid, as well as the movie Trainspotting. As long as you have taken care to deny plausibly that you had anything to do with that video becoming public, and that someone else (no idea who that was) took it from you and posted it, there's not much that can be done about it.
Mind you, these are my interpretations of current U.S. media laws, based on courses I took in the field. They do not condone any action you might take, and should not be considered an encouragement towards revenge.
Although, having gone through something like that myself many years ago, I have to agree that revenge, while arguably not the best course of action, and morally reprehensible, is nevertheless the only thing that guarantees satisfaction. If you can be Gandhi-esque enough to leave it all be as it is and turn a new leaf, fine. Otherwise, you can definitely request a meeting with the head of the graduate studies at her school and give out the information you posess (in the most calm and dry/professional manner you can muster), and even play pranks with other stuff you might have in your posession.