Given the nature of the topics being discussed, there is the possibility for harassment of other users.  Is there a way to keep records of posts, private messages and I presume it is called 'instant messages' between users?

As a use case a person claims a credible threat was made against them.  Person responsible for this threat most likely would delete the comment or post and I have no means of verifying what was said.

A means to keep a log file would be ideal where I could craft a cron job to offload to another machine such logs.