No I don't think people should report a "crime" here at all for several reasons.
The short time I have been here, this almost seems like a safe haven for some women, who can use the anonymity of the net to talk. That is important, it's less personal than a phone call. I don't think this facility should be put at risk, as it seems to help so many women.
Secondly the police couldn't really do much although in theory they could trace the IP, it's messy there will probably be DPA issues and I am sure it is not just that straight forward for the police to get info. So they may be reserved in acting unless they have good grounds. I mean lets be honest in a lot of these threads some crime has been comitted, be it assault, theft, abuse etc.
There is also the very inportant factor that this is the internet, no one knows what is truth or fiction, it's a shit stirrers heaven.
I have already seen grudges, stalkers, and trolling on here already. It would be easy to make a rape/abuse thread wouldn't it and leave markers to a person in RL, when they are innocent, or revenge, find out your DH has cheated and come here make up a story and knowingly drop hints.
It's entirely different to making a judgement call in real life IMO, when you can make a balanced choice and form a balanced opinion, on the net you can't.