Choose carefully! As of July 10th, you cannot change this once it is set unless you ask the site admin (me). Club admin controls should get the ability to change privacy once we are out of Beta.
Everyone can see the club and its posts, and can participate without joining.
Everyone can see the club and its posts, but only members can participate. Everyone can join.
Everyone can see the club and who's in it, but only members can see posts and participate. Users need to ask a leader to join.
Only members can find the club and see its posts. Users need to be invited by a leader to join.