Internet Law: Can leaked photo, video, email, information (any kind of) be sold online legally?

Let me preface this saying that I am not a lawyer, but I had some IP law training in the past. For copyrighted materials (definitely photos and videos), then it would be copyright infringement to distribute and sell the content without the express consent of the copyright holder. If there are people in the photos and videos, then it could be against the law to sell the content without a photographic release that authorizes you to use the subject's likeness. Most types of non-public personal information would be illegal to share / distribute in many jurisdictions, but most certainly personal health information and information covered under various confidentiality laws, such as attorney-client, would be prohibited). Public records can and are already widely sold. The fact that a web-site acts as a middle-man isn't particularly relevant. If the information is improperly distributed or gotten illegally, the operators of the web-site would be just as liable under most circumstances. Further, if the information was obtained in a manner that violated the law, the web-site could have additionally liability stemming from abetting the criminal activity. Whether the information is sold to a private party or made public is probably not relevant except in calculation of damages. An unauthorized third-party for all intents and purposes is "the public".

I don't know the answer, but you might consider asking on Avvo - http://www.avvo.com (full disclose, I'm the CEO of Avvo).  We have tens of thousands of attorneys answering questions just like this.  If you are thinking of doing this, I would definitely consult a lawyer.