it is safe to say that with the current "freedom" this forum offers to it's members, there is nothing much that can be done , if you really care about that board (most members don't ) then simply start reporting spam/off-topic posts.
It would be useful to give an incentive to those who make a report (positive),certainly this would increase the reports.
I do my possible, surely others might help, but an incentive could be a further boost.