"Registered" group automation.
Creates groups for registered users.
Must be called explicitly or hooked into activation.
As of Groups 2.2.0 this does not trigger the 'groups_created_user_group' action for each entry.
Initialize hooks that handle addition and removal of users and blogs.
wpmu_new_blog( integer $blog_id, integer $user_id, string $domain = null, string $path = null, integer $site_id = null, array $meta = null )
Create "Registered" group for new blog and add its admin user.
user_register( integer $user_id )
Assign a newly created user to its "Registered" group.
add_user_to_blog( integer $user_id, string $role, integer $blog_id )
Assign a user to its "Registered" group for the given blog.