Network Privacy plugin by Ron Rennick adds 2 privacy options in a single install and 3 in a network install. In a network install the network administrators (Super admins) have the option to set the privacy setting for the entire network. When the privacy is set for the entire network, the extra privacy options are not shown on individual site’s Settings -> Privacy.
Features
In a single site WordPress install adds the following privacy options:
I would like my site to be visible only to Site subscribers.
I would like my site to be visible only to Site administrators.
In a WordPress network activated on an individual site adds the following privacy options:
I would like my site to be visible only to Registered network users.
I would like my site to be visible only to Site subscribers.
I would like my site to be visible only to Site administrators.
When Network Activated or in the mu-plugins folder in a WordPress network adds the following:
A privacy selector in the Super Admin -> Options page to allow individual site privacy or the 3 above across to network.
If the network setting is individual privacy the Super Admin -> Edit Site screen has a privacy selector.
Plugin homepage: http://wpmututorials.com/plugins/network-privacy/