Due to the increasing amount of spam that is getting onto the forum, we have taken the decision to moderate the first post by all new users.
What this means in practice is that if you register as a new user and make a post, this post won't be visible until a forum moderator has approved it/. Once a new user has had their first post approved, further posts will not require moderation.
I realise this is not a perfect solution but it seems to be the most practical one at the moment. Perhaps, if and when the spammers give up, we will be able to relax this policy in the future.