1. Site admin can make the site invisible to guest users. This can be
done in admin panel>>Privacy&Permissions>>Global
Privacy. Option is called "Guests can view the site": yes, no, with
password. This setting is applied sitewide.
2. Oxwall offers "Privacy" plugin. You can download it from the store.
Once the plugin is installed, your site users will get a "Privacy" tab
under "My Preferences" ( can be found within the drop down menu of the
top right console in 1.5.x versions of Oxwall). Under this tab user
himself can select which content he would like to be private/public (
available options: only me, everybody, friends only). So if, for example
I have set my photos to be visible to friends only, those photos will
not be visible to users who are not my friends. Which means that guest
users won't be able to see these photos as well. Same applies to other
user content.
3. You can use "User roles" feature to restrict guest/users
from seeing/doing certain content/actions. Go to admin
panel>>Privacy&Permissions>>roles. There you can set
what kind of things user with "Guest" role can or can't do. For example:
search users ( yes/no), view profiles (yes/no) and etc.
4. Use, "restricted view" feature mentioned by
Shaun in the post above, to make your widgets visible only to certain group of users.