It is not a ban on starting threads or replying though - you reply to a thread or start a topic, the post is submitted but hidden... once a mod has once overed the post, they approve it, it is "un hidden" - (12 hours at the most I would guess).
There are multiple ways it can be handled, and over in Mod Land, we are also having a simultainious discussion about the pro's and con's of all alternatives and the nitty gritty of the implementation - and by extension how we can limit the inconvenience to new members whilst knocking the posts we don't want on the head. What ever solution is decided on over there will have been very thoroughly thought through before implementation.
-Mac