Am I missing something or is there no way of protecting discussions from being read?
For example I remove all permissions by default.
I create a group and give the group "View Space" permissions at the root space so that the person in that group can navigate to another space. (without this how can he get to another Space)
At that point he already sees discussions in the "What's New" panel on the "home page" and can read them?
Explicitly disallow view permissions for the space you want to hide the discussions in, and then add permissions for the group you want to allow to see the space. No users outside that group should be able to see the space at all.
Is this what you're looking for?
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