Dr Bubb,
You have an established site here, which means people do want to join and take part in your community.
You may be aware of the major spam problems my site has had, I have experimented with an advanced user registration process, to stop
bots and to deter further captcha smart bots I started experimenting with a paypal validation fee of 1 penny.
Since starting this, over the past week, I have had 7 new papal payments.
I think this is the future for online forums, considering the astroturfing and spam problems.
You must update your forum first though. And back up, back all this great information up.