There were no previous restrictions in posting for new members, only in adding links and graphics to their posts (until they reached a certain number of posts). Under the setup we are testing now, they can only respond once their account has been approved, which is usually within minutes, but might take a few hours at most.
Just to clarify: it's a one-time user account approval, not a per-post procedure.
We implemented the same policy on our cycling forum and haven't had a spammer there (or for that matter, complaints by impatient users) in almost seven years.