Okay....
Set up a new group - mine is called 'Regular Users' - give this group permissions like use shoutbox, send/receive PM's etc.
Set the post count of this group to 10.
Then remove permissions from the users group - I would suggest leaving the max PM's to 1.
Then when someone has made 10 posts they will get the permissions.
For existing users once they have made a single post then they will join the regular users group, as long as their post count is greater than 10.
I have also edited the error message when they try and use the shoutbox for example and do not have permission to explain this, so that I do not get any complaints.
