Tomos at Wikipedia wrote:
Another question is if things like social reputation and privacy of a japanese citizen is protected under any U.S. law. If not, the implications include that Japanese admins should refuse to remove a content which violate privacy of a japanese citizen, written in Japanese, even when the victim asks to do so. As you can imagine, that this is against some peoples' ethical standards.
It's o.k. to delete anything that violates someone's privacy -- not because of the law, but because we're writing an encyclopedia, not acting as a faciltator for bad behavior of any kind.
In any specific case, you could ask me what to do if you aren't sure. If I were to tell you "no, don't delete that", then surely your obligation under Japanese law would be satisfied, as you would no longer have the right to delete the material.
--Jimbo