There is legislation in place to deal with written forum posts which were passed by the house of lords in 2006 in relation to racial hatred and the like but there is nothing that covers anything else.
If you are talking about slandering someone in a post or saying anything thats un-true, ie you being slandered, then the only thing you can do is get the foum mods to remove it. its not a criminal offence, more a civil one....
maybe if you elaborate further?
it's not on here, it's on google reviews, and an issue with "loss of earnings" regarding a review i put on there.