The deal is that the hard drive is broken into SECURE areas. Each user has their own space, and only that user can access it.
There is also a SHARED directory in /Users/Shared that is available with guest access to everybody, as well as Public directories in each user's home folder that allow anybody to read what is in there, though only that user can write to that directory.
This is good thinking. Leaving a system unlocked for anybody in today's wired world is a surefire way to get all your files trashed by a bored hacker. Granting full access to your ENTIRE disk is foolish, but setting up access to selected areas is much more secure.
Let us know a little more about what you want to share and how. We'll help you out.
