Would it reduce the workload for moderators if new users could only create and post a single introduction thread item until they were vetted by the moderators?
Hopefully, the introduction post would be easily seen as legitimate or spam. If a new user has to wait a few hours before being able to post in general areas, then I don't think that is too bad a price to pay.
Or can Captcha be implemented for creating a user account and maybe the 1st 5 posts by a new user?