4
Actually its quite easy to add.
Ok a per user restriction...is pretty much outta the question, but thats where groups come into action, and since we can add users to groups, all is fine :o)
To implement this system, the only thing that needs to be added is a table field that holds the groupid. So now when you create a new download category, topics category, or weblinks category... you can select a group that has access to this (of course there should be a default value to make things easier)
Now if you said the anonymous/registered group (should prolly be the default) can access it, then you have nothing to edit. However if you'd like to make it acessible only to friends, then you would create a friend group, and add all those individuals who you want to grant access to your newly created friends group.
Now since each category branch has an associated groupid, we just need to check if the user calling a file, document or whatever from this branch has the necessary group permissions.
Ok this does mean editing multiple files, but the principle is rather easy to achieve.... just dont count on me making any hack like this before the final version comes out (and even so id only do it for the downloads section)