Is this directed to me?  If it is, I don't understand the question or the reason for it.  Whoever this question is aimed at, I don't think you can raise this issue where there are generally no true identities involved here, just pseudonyms, therefore no defamation of character.  You would have to be able to prove that you personally, not a fictitious name, was harmed in some measureable way.  This would be my understanding.