Just sharing my brand new forum http://thenetworld.com It has a generic theme and even more generic logo, but I'm fine with that my goal now is just to get members. I will be adding threads myself whenever I find something that needs to be shared on there. Added a adult section on there as-well seeing my thread here has had over 50,000 views and I think 1,200 replies. With no advertisers I put a pop-under ad, but when I get some I will remove that. Not a clone its a new creation that will evolve over time.
How are you liking MyBB? Post content and people will start registering. Also a good plugin to get is tabbed menu. Good luck with your forums.
Last time I checked there were quite some useful antispam plugins at MyBB. Have a look at their Download section. Good luck with your forum.
A good solution to this seems to be to require longer passwords. On two myBB forums that I created, but have done nothing with I required ten characters in the password. On one forum, it works great. On the other, the spammers have got around this.