Forum registration

[WellTell]

Well, I don't know where to put this, so here it is.
It is impossible now to register new users into this forum. I wrote an email to Mean and he manually registered me. However, no validating email came for a few days, when finally I'm here. Thank you Mean! I understand that you are bussy with many other things, that's ok. However I am sure there is some possibility to supress spammers and other mess in more sophisticated way than just disabling the registration. Even though it is the easiest quick solution, from long term view it is at least unpractical.
Does any one of you an idea of what to do with it? What method of authentication to involve to make the system robust?