When you create a new sub-site in SharePoint, and choose the Use Unique Permissions option, three groups are created at the site-collection level: Owners, Members Visitors. These groups are associated to the sub-site that you’ve just created.
But what does associated actually mean?
First, I misled you a bit – the names of the groups are actually SiteName Owners, SiteName Members SiteName Visitors (where SiteName is the name of the sub-site you’re creating).
Next, they all have a nice link in their description, directing you to the sub-site.
More interesting, those three groups get some permissions on the sub-site.
The less obvious associations are the fact that those groups will appear in the Quick Launch area when you go to the People and Groups section of the site. Also, if you delete the sub-site, the groups will be removed from the site-collection.
Lastly, when you add a user to the site, you can either assign the user an explicit permission level, or you can add her to one of the associated groups of the site.
That’s quite a lot of meaning for a single word. Let look a bit deeper into each meaning:
Title Description:
This is just some basic naming policy used by SharePoint. The SiteName is validated, the group type is appended, the description is generated with a link. Nothing fancy here.
Permissions:
The permissions are obtained by assigning permission levels to each group. Again, nothing too interesting.
Quick Launch:
The list of groups that appear in the Quick Launch is retained in the AssociatedGroups property of the SPWeb. This list can also be updated by modifying the vti_associategroups key in the AllProperties property of SPWeb.
Setting a group as the AssociatedMemberGroup, AssociatedVisitorGroup or AssociatedOwnerGroup automatically adds the group to the list of AssociatedGroups.
These properties can be also updated by modifying the vti_associatemembergroup, vti_associatevisitorgroup vti_associateownergroup keys in the AllProperties property of SPWeb. These three properties are also reflected in the Set up Groups page of the sub-site.
Auto deletion:
This issue is a bit more complex.
When using the SharePoint UI, or when calling CreateDefaultSharePointGroups methods of SPWeb, this behavior is implemented automatically. However, creating a group, and even associating it with a site, doesn’t reproduce it.Only after using Lutz Roeder’s .Net Reflector, and examining the CreateDefaultSharePointGroups method, I’ve found that you need to add the group’s ID to the vti_createdassociategroups key in AllProperties.
Adding Users:
When adding a user to a sub-site, only the groups listed in AssociatedGroups are listed as possible groups for the new user.