Jive allows you to create content within your personal container, where you can chose to have it be hidden to the rest of the world, shared with a few people, or completely open.
You can create / move content into a 'place' (community, project, group) where that content now abides by the rules of the place. So your once 'hidden' content, when moved into a secret group, is now just available to anyone within that secret group. It can not be both hidden / private & live within the secret group, you must chose one.
That make sense?